I recently (the other day) purchased a 2005 X-Type Sportwagon 3.0 (Hi everybody!) and it came fully equipped with a check engine light and the P0171 and p0174 codes. I read everything I could about this before signing and then took it home anyway. The patient has 168,000 miles on it. Engine idles extremely smooth, runs great except for the hiccup (the lurching) which it does NOT ALWAYS do, but does do more often than not, doesn't matter if cold or hot engine. No other codes beyond a pending 1111 and a pending 1796 gearbox fault code (and the P0171 and P0174 codes show up in the pending file as well as the active or current file). Anyway, it needs to be fixed.

Troubleshooting so far:

1. PCV hose is the ribbed (or more accurately checkerboard?) design, not smooth, looks good but not exactly new.
2. The corrugated hose from airbox-TB does not appear to have any splits in it, I took it off and bent/looked into every crevice.
3. The Brake Booster hose looks new/clean and the valve seems good, no issue with it visually.
4. Sprayed carb cleaner on all of the connections, no change in idle noticeable *have ordered better scan tool to watch fuel trims, it's en route...
5. The Brake Booster fitting looks to be the newer one, I unclipped the hose (push down and then up) and THINK I see the O-Ring in there. There is a bit of play in this fitting when inserted, both side to side as well as up and down, is that normal, i.e. it wiggles a little bit or should it be super snug like it's actually bolted in? Again, spraying carb cleaner on it didn't change anything.
6. Clamps holding corrugated hose were very loose, took almost no pressure to release the screws. Tightened down all the way when re-installing. I think the clamps are replacements, they are a little wider than the molded channel on the hose itself.
7. Purge line has the silicone caulk or whatever it is fix/blob on its fitting area on the manifold. When sprayed it seems fine, i.e. no change. Have ordered new correct fitting, don't want to remove it until that arrives. May need to source a new hose or find a junkyard one...
8. THE BIG QUESTION: I removed the covers for the IMT and IAC actuators on the back left of the intake manifold. Since it's a 2005 I was expecting green/blue O-rings but kind of hoping for obviously failed yellow ones, but they are BLACK? Could these by my culprit? They seem to fit fine, but aren't at all oversized, i.e. they just kind of fit into the channel/groove but there may be a little play laterally. When bolted down it's all very snug. Spraying carb cleaner didn't do anything there either. But I'm wondering about that as I have never read of black ones on here. Turns out though that Felpro seems to make a black set sold at AdvanceAutoParts...(their part 72946). Not sure if that's what these are but I could see someone getting those...
9. The CarFax on the car does show that earlier this year, presumably when there was a code thrown for the previous owner, a shop 1. "throttle/throttle body checked" and 2. "Intake Manifold Gasket(s) replaced" and 3. "Engine Powertrain Module checked". So I'm assuming that the gaskets were in fact changed and the car did have its registration renewed after that. Of course the shop could have screwed it up and/or the lowers could still be an issue I suppose.

The car was traded in soon after that event, I suspect the check engine light was on at that time. The last emissions check it passed (light would fail it) was May 2020, reg was renewed. In April 2021 it went in for the above (#9) work having only traveled a couple of thousand miles since the year before (pandemic? Spare car? Trouble?. Then reg was renewed again but here it's only required every other year so I assume the owner may have decided to cut their losses and realize they'd have issues the next year...

So my thoughts are:
1. Replace the black O-rings with the C2S40669 green/blue ones unless people think the blacks are fine? Cost for the real ones is around $30 from what I could find.
2. Take apart the Purge Line, and use the proper fitting when it arrives (on order(
3. Replace the MAF sensor? Seems easier than digging to the lower manifold gaskets to start, perhaps find a junker one (realizing it may be bad too of course)...
4. I guess get into the intake gaskets, both upper and lower.

What am I forgetting?

Thanks!

What's the little rectangular box to the left of the corrugated airbox-throttlebody hose that is connected to it?

 

No Hat, welcome to the Forums. Lots of good info here and I am sure we can get you fixed up. Please stop by the New Member Section and do an intro there. This will let you meet those that make this place what it is that you may not meet in this section.

As for your problem. I would start with getting the green o-rings. They are a bit different in that they are made of a much harder material and will not give like the black ones that you have in there. From what you describe, they do sound a bit loose to me and may be the source of your problem. The next thing I would do is get a can of throttle body cleaner and remove the intake off of the throttle body and if you see brown, spray it away. Pay particular attention to the edge of the butterfly (the silver disc blocking the air flow). This is known for getting a bit of varnish on the edge and causing it to stick which will throw things for a loop with the car. If by chance you happen to flood the car, do not worry. When you go to start the car, depress the gas pedal down as far as it will go (I know, you are thinking I am nuts right about now). Then attempt to start the car. As it starts to catch, ease off of the gas pedal and bring it to idle. This is an override that is built into new cars to help them get beyond a flooded condition. Depressing the gas pedal all the way on starting actually turns off the fuel injectors.

From here, i would do a smoke test of the intake to see what you see. After that, I would make sure to clean the MAF sensor.

That little rectangular box on the intake, that is a noise suppression box. It works by allowing air to get in it. As the motor pulls more air from the valve for a cylinder opening up, this box acts as a surge volume and lets air flow from there, making the overall air flow more consistent. As the air flow slows, the box refills.

 

Great, thanks for the info!

I ordered the green O-rings this morning, will install as soon as they show up. And thanks for the other suggestions too, those will follow...I'm hoping it's the simple o-rings.

I stopped by a junkyard today and found a 2002 sedan with the engine already opened - but I opened the IMT covers and found....yet another set of the black o-rings! But I was also able to pull a Purge Line off of that car, so now I have a spare for when the new fitting arrives. Sadly the MAF was already gone though.

Do you suggest clearing the codes after every "change/correction" to start with a new baseline? I assume they won't go away by themselves in general. Or better stated, if it does the bucking/hesitating now and I change something such as the O-rings, do the codes have to be cleared to stop it from doing that or will the car just work correctly if that fixed it and then the codes clear themselves after a certain number of drive cycles are complete?

I'll go do an intro this evening, wife wants to go for a walk right now, thanks!

 

No Hat, will the codes clear is a question that has been asked and has a yes and no answer to it. When you make a repair and do not clear the codes, the check engine light (CEL) will remain on. It will remain lit for 5 drive cycles (about 5 minutes of running the car, it needs to see a minimum of 10,000 revs of the engine and it get up to temp for each drive cycle). On the 6th start (assuming that the previous 5 drive cycles did not experience the fault), the CEL will turn off. With that being said, the codes will still be able to be called up in the computer. This has lead to some confusion in the past with people posing problems. So, I would say if you make a change to correct a problem, it is advisable to clear the codes and see if they come back. Otherwise you have to do a lot of driving to see if the code clears.

The codes will not cause the car to run rough or continue to make a problem occur. The ECU controls the engine, the codes are simply an indication of what the ECU sees the engine doing.

 

Today the green O-rings arrived so:
1. Replaced the black O-rings with green ones, applied a very thin layer of engine oil to them once installed before pushing the units back into the intake. No change, car bucked at 3k rpm. Green rings arrived in a clear bag, not a Jaguar branded bag. Assuming I got factory items but it was ebay so who really knows. They seemed very similar to the black ones in all respects.
1a. replaced air filter at same time, it was filthy.
2. Took MAF sensor out, cleaned with MAF sensor cleaner. Sprayed the wires down the tube 3x and waited for it to dry between sprayings. Reinstalled, no change
3. Removed bellows pipe, cleaned throttle body plate with throttle body cleaner. A fair amount of dirt/buildup on there. Got it looking nice and shiny including the lower edge (that tilts out towards the front when opening) and corners of the plate at the hinge/center. Noticed that when in "resting" position it is possible to still push the bottom of the plate IN (towards the back of the car) maybe 1/8" of an inch before it hits the stop, but upon release it moves forward again on the spring. I assume this is normal? Buttoned it all up again, tightened clamps, made sure other hose outlet to the little box was connected. Drove, it bucked again. BUT upon continuing to drive it stopped bucking. Perhaps it was just heated up and that sealed something, who knows. Will try again later after it cools down. It's done this before (given the false hope of success before crushing the soul again a few stop lights later...)

The intermittent nature of this is somewhat frustrating, i.e. it doesn't do it every time. I did NOT clear the codes between fix attempts. Engine light is still lit, very X-massy, 'tis the season and all. At least all these little things are easy to check/fix/improve and easy to access. So far at least.

Next steps if it comes back:
A. The little intake fitting is still en route, when it arrives will remove the glob of silicone on the purge line where it goes into the intake and try to install the little fitting correctly. I also have another purge line I picked up for a dollar at the junk yard from an '02 that looks good so may swap that out too just to try it then.
B. Remove and fully inspect the PCV line. It is the ribbed/waffly one but it looks somewhat older. Has a Jaguar sticker on it. It looks ok, but I haven't looked at the underside of it. Do people just replace or it either looks good and works or it's obviously faulty? Seems like the waffly one like mine is the "good" design from what I read.
C. I suppose bite the bullet and do the intake gaskets, they were supposedly done per carfax but no idea if just uppers or lowers too or if it was done correctly. I would do both sets and replace spark plugs at the same time.

I've got quite the little menagerie of chemicals on the shelf now...

 

While you have some time under the hood, you might want to give the MAP sensor a clean as well (intake manifold after the throttle body).
Also worth checking the condition of your ignition coil common earthing connection which goes onto the generator bracket.
Earthing points are a common cause for a wide range of oddities on our cars.......undo (noting order of lugs if multiples), clean the lugs with find sandpaper, scotch pad or steel wool along with the landing on the chassis and reassemble.

The PCV tube (waffle design) I believe has a tendency to collapse under certain engine vacuum conditions when it gets older, I think it was replaced in later production by a rigid plastic tube and rubber connection pipes.
Might be worth seeing if yours is doing that at the higher revs, but not sure if that could induce the problem you are seeing at 3000 RPM.

 

No Hat, if you are getting into the intake as far as you are talking about, I would save myself a lot of questioning myself and time later. Get the upper and lower gaskets and do the plugs at the same time. If you are having a hard time finding the upper and lower gaskets locally, ask the parts guys for the upper and lower gaskets for the same year Lincoln LS 3.0L engine. They are the same parts. As for plugs, KISS. Our kitties do not like the fancy split/multi-spark spark plugs. A good (double) platinum plug is all you need. The big issues most people seem to find is on the back wells, you may find some oil in the plug well which can lead to misfires. But, these are noticeable at all RPMs.

Something just struck me and I think you may be confusing things together here. Our cars have a safety feature to them. If they see the engine not running right, they will put a message on the instrument cluster saying "RESTRICTED PERFORMANCE". When you see that, the computer will not let the engine rev above 3,000 RPM. So, that might explain your bucking that you are seeing. This is the engine turning off the fuel injectors to bring the engine RPMs back down to under 3,000 RPMs. This is where the error codes will point you to where the ECU sees an issue and is putting the restriction on the engine. The P0171 and P0174 codes will put the engine into this mode. So, solve the vacuum leak, the bucking will naturally go away. So, if you were able to drive normally, then you have gotten atleast part of the problem solved.

 

Mark - Thanks, I will add the MAP sensor and ignition grounding items to the list to take a look at / clean!

And thanks re the PCV tube, yes it will let me rev it to redline on the occasions it doesn't hesitate. Or more correctly, even when it does hesitate once I let off the gas when it stumbles, it then generally lets me drive through/past it and on up the range.

 

Thermo -

Thanks, yes of course, plugs would be done at same time if getting into the intake and no reason not to do both sides (upper/lower I mean). Re plugs I'm thinking the Ford Motorcraft ones are probably fine unless there are strong negative opinions otherwise...

I am NOT getting a Restricted Performance message. But I am getting the fuel cutoff at about the 3k mark. Driving it again just now it was not cold but cool and the first time I revved it it cut out, but then the rest of the way to Costco it revved fine and past the 3k mark. Coming home after an hour at the store the same thing. Not fully warmed up it did it, but once warmed up it worked fine. So if anything I think it's (currently) improving - or likely a multi-part issue and I may have solved part of it but there's still something outstanding.

Beyond that issue it idles, runs, and revs very smoothly.

Thanks for your help!

 

Mark - When you say "generator", I think that's what we call the "alternator" in US English, correct? And the bracket would be on top of it from what I can see, there is ONE lug attached to it with what looks like two fairly slim wires emerging from the coil wiring bundle. The lug and screw look far from clean, just want to be sure this is the place you mean. It's just about in line with the oil filler cap (offset to the left a little bit when facing the engine) and under the black hose about 6" below the top of the radiator support. If the hose wasn't in the way it'd be clearly visible from above.

 

Yes the alternator is correct, I was staying with Jaguar terminology of their schematics "Generator Bracket" and the grounding point being denoted as G17AS.
There is only one grounding point on that bracket, so you will see a lug and wires tying back into the engine wiring harness.
Yes it is on the upward face of the alternator bracket under the hose, fastened with a small hex head bolt.
Just worth checking, seeing you are having a misfire issue.

 

Thank you, I will clean it tomorrow when it's light out again, that seems to be the same one I was referencing, one lug in my case. I did the MAP Sensor a little bit ago, cleaned it and found that the o-ring in there still seems supple and doing its job, still same condition after a test drive but thank you for the suggestions, no cost to either of these...

 

Latest update and questions:
1. Ignition ground disassembled and cleaned - It was just the surface that was dirty, all mating surfaces were shiny and in full contact, looked like new and never disturbed. Reassembled, no change. Thanks for the suggestion though!
2. Took PCV Valve out and line off to check.
2a. The line is the waffle-pattern one, it was soft, supple, and no damage evident, I looked all over it and bent it every direction looking for issues. Is there a newer RIGID (solid tube) design? Or is this rubbery one the newest? It's not floppy but it does bend. One of the clamps broke when disassembling so replaced with a good hose clamp. Other end seems to seal fine with the pressure clamp.
2b. PCV valve was quite oily and frankly looked old so bought a new one and installed it. I thought this was the fix as the first drive from cold was perfect, and as it warmed it no issues either. Second drive started out good, but after stopping, idling for a minute while my son got stuff out of the back, after that it started cutting out at 3k (actually a little before) immediately.
3. Next I removed the silicone glob from the fuel purge line, removed that, found the plastic holder was cracked into several pieces, and the O-ring was only half there and very hard. Removed all the visible pieces, cleaned it, replaced with new O-ring and plastic piece (tossed the new brass piece). Retested, still same issue. The line looks and feels fine, I do have a (also used) spare, I suppose I could put that on too to re-check.
4. I also pulled out the fitting for the brake booster line and removed the plastic ring and O-ring. Both seemed new and still supple so I reassembled. This whole part looks new, I think someone has been in there before and replaced that not too long ago. The plastic and O-ring were like my new ones, not like the Fuel purge line one. The brake booster line and valve look like new as well which they likely are.

I have to go out of town for a week or so, I suppose next steps (since I seem to have one or more oil leaks anyway) is to order all the intake gaskets inside (upper and lower) and new spark plugs. I guess I could do a smoke test as well. Supposedly the intake gaskets were done a couple of years ago but no indication if just upper or all of them or if it was done correctly. I'd be doing all of them, (hopefully correctly...).

QUESTION 1: I'm thinking FelPro for the intake manifold gaskets and Victor Reinz for all of the exterior and boss gaskets? Any issues with those brands or items that I'm missing?

QUESTION 2: I was going to buy the Motorcraft SP479 sparkplugs as I think they were the OEM fitment but now realize they are single platinum. Realistically the car has 168,000 miles on it, Is there much point to going for more expensive plugs?

QUESTION 3: Should I replace the plug boots too? Any preferred source or brand for those?

Car runs absolutely perfectly (from an engine standpoint) otherwise. Besides the self-induced hesitation/cutoff at 3k rpm it starts, idles, accelerates exactly as one would expect and far than I would expect with the mileage it has. Extremely smooth engine beyond the issue.

Thanks in advance. I'm sure this issue is as tiring to read about as to deal with, now it seems the easier items have all been tried and it gets a little harder.

 

No Hat, for your questions:

1) I used Felpro on my X-Type and they worked just fine. The Victor Reinz products I am not familiar with. But, if you have used them in the past with good experience, then I would use them again.

2) Single/Double platinum, yeah, whatever. The big thing is the electrode on the end is platinum. This will be a set of plug that will last another 100K miles. Can you upgrade to double platinums, sure. They are like a $1 more a plug. Just don't go fancy. The Bosch +5's, Splitfires, etc plugs raise hell with the Jag engines. so, DO NOT!!!!! get them. A basic platinum plug is all that you need.

3) As for the boots, I would say if you can pull off a coil (#2 cylinder, right behind the passenger side headlight) is an easy one to get to. Rub the boot. Do you get a fair amount of black dust/crumbs off of the boot? If yes, then replace the boots. If you get next to nothing, then they should be good. If in doubt, replace them. They do not cost that much and could be a source of your misfires.

 

SUCCESS!!! WOOHOO!!!

After looking at everything again I replaced the Fuel Filter since the car for some reason came with a new one in the cargo area - but that didn't fix the stumble or Check Engine light. It was a long shot but since we had the part, why not. There was a Hengst filter already installed that didn't look too old so it was probably done by someone else previously. Now there's a Mann filter in place. Works just as well. I video'd the procedure and stuck it on youtube...quite easy.

So yesterday my son and I tore down the intake and swapped out the spark plugs and both the upper as well as the lower gaskets using the instructions I found on this forum. Plugs looked quite old, no manufacturer mark beyond looking just like the new Motorcrafts and also being made in USA with the full-length threads, so likely previously replaced. The old gaps were between .065 and .070 or even more. New gaps were .052(ish). It idles about the same. Coils were kind of a gray color, the replacement boots looked different than what was on there and I couldn't figure out how to easily get the old ones off so left them, they looked in great condition.

Notes:
1. If you're going to do the sparkplugs and are for whatever reason changing the UPPER intake manifold gaskets it's VERY little extra work to do the lowers, just do them, reading up on it I got the idea it was a lot of extra work, it is not at all. I am 99% confident that my lower gaskets were still original after 168k miles and less than 50% convinced that the uppers were in fact changed two years ago as stated in the CarFax when I bought the car. The amount of crud around the lowers was astonishing and the upper surfaces were pretty bad too. Both sets of old gaskets were green, FWIW. I'm guessing someone just changed the IMT gaskets as they were a black color when I changed them recently and called that the intake gaskets. Perhaps it's no wonder the car was traded in with the Check Engine light on, how I bought it. My new gaskets are from Viktor Rein, good quality, much beefier than the shrunken-looking ones I removed. Neither are green, uppers are reddish and lowers are gray.
2. After removing the four bolts to get to the lower manifold we could initially not figure out how get the black center portion out, thought there was ONE bolt that held the fuel rail on at the front that we could not see as but needed to remove as someone said. Eventually we took out all those top fuel rail bolts (6) as well but it still wouldn't budge when trying to lift it. But finally a little SIDEways pressure from a screwdriver wedged in next to it popped the whole black portion (that sits between the upper and lower manifolds) loose. That's all it takes, a little lateral pressure. The Fuel Rail could stay in place, did not need to remove those screws after all. What held it in was all the gunk around the it. Upward pulling had too much suction against it I guess.
3. The "hidden bolt" behind the manifold is a b*&^% to get off. Best way seems to be to remove all the electrical plugs at the back left (three), then remove the two other bolts in back and then push that harness all the way back to the firewall and with a gloved hand get back there and turn the bolt after breaking it loose the best way possible. That's unless you have a huge toolkit with lots of bendy bits that I don't have. Or daintier hands than me.

Doing all the plugs and those gaskets (upper and lower) took us about four VERY leisurely hours. Doing it again I'd bet we could do it in under an hour and half on this car and under two hours on a car that had never had it done. The most time consuming part was keeping everything clean and cleaning the mating surfaces, the wind picked up something fierce and we had the car partly outside. We are not repair pros, but relatively handy, regular people with regular tool kits.

We sort of stood the upper intake on its side and wired it to the hood strut so it would stay up and out of place while we worked lower, the TB stayed in place. After a few minutes we realized there was quite a bit of oil that came out of the intake and collected in the accordion hose. We mopped that up at the end but it was likely at least a tablespoon which was a bit shocking.. We'll keep an eye on that, we've replaced the PCV and the hose is fine. Looking down at the top of the valves and in the intake there is definitely more than a bit of buildup on them. I guess we'll do a few more Techron cleanings and maybe eventually a Seafoam or similar...But it runs very smoothly so maybe not.

Anyway, the FIRST drive afterward had us dispirited as it still stumbled. But after shutting it off and restarting it worked great, then after a few cycles the light went off too by itself for the first time ever and no further issues. Today no issues either after starting from dead cold so I went for the emissions check. For whatever reason they only checked my gas cap and OBD, never hooked it up to the sniffer, and just passed me and charged me the $25 fee. This is in a state-run facility that has four-wheel dynos, whatever, first time in over thirty or so emissions checks that that has happened to me...At least now I can register it in my own state next week and am good for the next two years at least.

Thanks for the help from everyone here. Now it's time to start the next phase of this project, I'll post some new questions soon... Thanks!