And wasn't it Ole Doc Gross who responded with "...a bad coil can....? Happy to hear she's once again purring.

 

Actually it was "thep". thanks to all AWESOME site.

 

Glad to hear it worked out for you and did not cost so much. Just a reminder though that the coil packs and spark plugs can fail due to a spark plug tube seal failure. So if the mechanic did not note oil on the failed plugs/coil packs and no oil in the tube, you should be fine. If he did not check closely and you have more problems with restricted performance, you may want to check the spark plug tubes of the failed plugs/coil packs for oil before you start tearing your car apart.

A few months after I had my spark plug tube and valve cover gaskets replaced, I began to have restricted performance and it became more and more frequent. I had to shut down the engine and restart a few times to reset it and then it could be fine for a bit. I was afraid to drive in traffic for fear of it going into limp mode on me. The dealer couldn't find the problem after several visits.

After fiddling around, I discovered it was the wiring harness plug at the throttle body (carburetor). It had been disconnected by the dealer while replacing the spark plug tube seals and valve cover gaskets. It is a 4 prong mini banana type plug, if you know what I mean. What I did was slip a small flat screwdriver blade into the slot between and under under each spring tension section of the male plug and stretch the metal up very carefully to provide a little more tenstion or pressure between the male and female surfaces of the plug when plugged together. I did this to each of the 4 spring sections on each of the 4 male ends of the plug, cleaned it up and then plugged it back in. The engine has run flawlessly ever since.

It is easy to diagnose this problem. Remove the engine cover to gain access to the throttle body and while the engine is idling, move the wiring harness attached to the thottle body around with your hand. Not too roughly though. You do not want to damage the connector. If the connection is poor, the car will go into limp mode right away and the engine idle will be noticably rougher.

Have a Happy New Year,
Terry

 

Great info "thep", i will remember that if anything happens like that. Thanks again my man for the great info.

You have great New Year too, I will poppin bottles early tomorrow, Peace!!!

 

I know it was thep...my alter ego.

 

this jsut happened to me today!

ive been meaning to post about doing my 90k mile service which I will start a new thread for shortly.

mine has been pretty much running flawlessly for a while. minus the rattle i think from cats starting to go.

i always keep it in the garage and last night it was 25 for most of the night and was the following night. around lunch time i start it up and let it idle for about 5 minutes before i get in it. I back out of the garage only to realize i had forgot something and drive back in. its running while i go back inside my house and come back out.

when i shift to reverse it shudders a lot and doesnt feel like its in gear so i put it back in park. i get the restricted performance and transmission fault. yikes :/ *Prays extra hard*

turn it off wait 5 secs and turn it back on, just restricted performance this time and some low RPM vibration. The throttle is very hesitant/non responsive. carefully drive about a mile or so down the road to get lunch while calling my buddy that runs the service shop i take it to.

after lunch start it back up and just get a CEL and rough idling, ok were getting better, THANK GOD! notice that its only idling rough and cruises fine. getting a slight engine knock noise.

my friends jaguar tech didnt have time to properly trouble shoot the car and scan the codes but we all seem to agree its a coil going etc.

on one of my Lexus it had a coil go and the vibration was WAY worse. of course i could still have a coil gone and this car is just smoother.

i also notice a chugging noise from the exhaust with different bursts of air then normal and smells possibly of unburnt fuel.

 

Sounds like a bad plug and/or coil pack. I would recommend the mechanic looks for oil on the spark plug above the threads to check for the leaking spark plug tube seal. They may be failing more frequently if you have changed to synthetic oil some time ago. Earlier versions of synthetic oils could cause problems with engine seals. However the new synthetics have been balanced better to control seal expansion/contraction and softening. See the threads regarding synthetic oil and engine seals on the "bobistheoilguy.com" forums for lots of info on the subject.

I had 3 spark plug tube seals and a valve cover gasket fail at 64000 km (50,000 miles). Then the rear seal failed the day I got the car back from the dealer after the repairs.

Best of luck
Terry

 

Hello all I am new to this forum so forgive me if this in not the proper way to post. I have a 2003 Jag S-Type with a restricted performance + gearbox fault and it will not even turn over to start. I had a full tuneup done 2 weeks ago is the only thing different that has been done. Any ideas?

 

You'd be better off starting a new post, but welcome to the forum.

First thing to do is have the codes read as discussed above.

 

miles, buy her a new battery.

 

I too have a what seems to be transmission issue with my 03 str which has 134000km. The car slightly jerks from 1st to 2nd but other gears seem to upshift and downshift fine. only when im going from 1st to second the car jerks, i am wondering if anyone can give me some advice. do you think a tranny fluid change will help or does it sound like something else all together? Im selling this car soon and prefer fixing these odd issues to the best of my ability. I would deeply appreciate if someone could point me in the right direction.

 

Hi from Calgary 03Styper1919. If I am not mistaken, this Jag model year was the first to use the German made ZF 6hp26 transmission and it had a few issues with harsh shifting. It was also used in some BMW models and such as well and they also had some issues with harsh shifting.

In this forum there is a lot of discussion about this issue and much of it can be found under "the lurch". Also, from other sources refered to in this forum, I found discussion about cleaning the shift control valve moving parts (hydraulic valves) inside the transmission, of a fine build-up which deposits on these moving parts. These deposits may cause the moving parts to stick, supposedly causing harsh shifts. Some repair shops clean these parts when trany service is done.

I recommend searching under "the lurch" to start with and doing some reading. It should help considerably in understanding the problem and give you some ideas as to how to improve the performance of your transmission. Also I recommend you check your transmission cooler lines for leakage at the radiator after dropping the belly pan (7 bolts).

Best of luck.
Terry

 

Good advice there, and do have a look in the How Tos. Check the pair of bolts for the shifter cable on the side of the trans.

Now, it just about could be an engine issue as they often upset the trans, so bear that in mind if you draw a blank otherwise.

 

I have the same issue with the message restricted performance being displayed. However when codes are pulled from the car, it shows only bad O2 sensors on both sides. The car doesn't sound bad, doesn't run bad, but when you try to accelerate it bogs down and starts coughing at 3000 rpms. Any ideas on what could be causing this because outside of the O2 sensors running lean it runs perfectly fine in town. Only during acelleration does it bog down. Ideas?

 

I'm very familiar with your STR's CEL w/RP. She's in protective mode (the 3000 rpm rev limiter cuts in to preserve the motor) due to lean condition instigated by failed O2 sensors and/or vaccume leak. Start with replacing the O2 sensors (affordable from rockauto.com). You don't need the most expensive sensors. I believe I paid $60/sensor or less.

 

If you have allowed the car to be driven like this for very long the catalytic converters might be damaged.

It would be worth a look inside the pipes to see if the honey comb is intact or collapsed/blocked.
.
.
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It was me who suggested burnt coil.

 

how do you get the codes for the car? the arent displayed on my dash?

 

Code Scanning Tool/Code Reader.. Most Auto Parts Stores Will Scan Codes For Free. Just Go In And Ask.

 

Buy an OBD tool with live data. Such as elm327. About $15. Tons on ebay