When I come to complete stop and engine goes to idle it begins to run really rough. It doesn't die, but does shake the car. Took it to local mechanic and their analyzer did not go back beyond 2000. He said it sounded like one cylinder wasn't firing , but said that without an analyzer he couldn't tell which one! Made an appointment with Jaguar of Columbia(SC) and took it in this morning at 7:30am. 11:30 no word, called, had not looked at it yet! 3:00pm, no word, called, no one knows anything. Ten minutes later, get call from Jaguar guy telling me that they haven't taken anything apart, BUT it SOUNDED LIKE it COULD BE a timing chain that jumped a cog. He said if it was an upper chain it would cost between $1500 and $1800 and if it were a lower chain it could go as high as $3500. Could a timing chain jumping a cog cause it to run rough only at idle? Once I'm moving it smoothes out and purrs like a kitten. Any ideas what might be wrong? There are no warning lights at all. Also, when you start it up in the morning and start out there is a very loud flutter from under the hood for a few seconds and then normal. Any suggestions would be greatly appreciated. Thank you.

 

What OBDII codes do you have or did they pull?

 

And what fuel trims?

 

As Gus said folks here will use the codes you provide to start diagnostics. Since you probably paid a service fee you can call back to the dealer and ask them what if any codes were read on their equipment, and check your paperwork from the service to see if they indicated any, if not then ask them when you call why none were listed (gives you some leverage on them not providing proper information from their diags and your fees you paid for said info).

You have a boat load of miles so it could be anything from air intake (trims) to fuel presentation to bad plugs or coils etc. Many of these symptoms show up with a code and usually a CEL which you don't have (the CEL does come on when the key is in the 2 position? burnt out bulb?)

The car if missing on 1 cyl would 'appear' to smooth out with increased RPM in a v8, doesn't mean it's not still misfiring.

 

They didn't get any codes. I don't think they even hooked it up. And, I'm sorry, I don't know what fuel trims are. Are the OBDII code readers expensive?

 

You can have the codes read free at autozone, etc.

 

also try removing the big plastic hose between the airfilter and the carb {throttle body} buy some throttle body cleaner and spray and wipe down everything in there {s/b back of the engine in the center) a build up of deposits will cause the rough idle especially if the battery has been removed and reconnected . the computer says its a new car and the computer is expecting a perfectly clean throttle body and this isn't the case probably the computer adjusts as you drive the car . also clean off the mass airflow sensor (on top of the same hose between the filter box and the throttle body near the filter box) do not handle the sensor bulb it is very fragile just spray down and let air dry if possible try and remove all slack from the throttle cable also. buy separate cleaners for both. not sure if ones is to strong for the other. smoothed out the idle for me .

 

Bob, I know 'Smith is common' but you didn't happen to have family in Ohio? I had a cousin who's son was Bob Smith Coached college basketball in SC. Just would be a interesting chance, haven't seen any of them in years.

And in regards to your visit to the dealer, those Jag mechanics are wizards, they must be clarivoint to tell you something without even connecting to read codes.. what did they exactly do for your hard earned $$ ?

 

Used to live in Ohio, but I don't think I have any family up there anymore. They moved the car and popped the hood, but beyond that I don't know! They were going to charge me $145.00 for diagnostics, but when I picked up my car they said no charge?

 

Thanks for all your input. I ordered a code reader yesterday and as soon as it gets here I'll come back on and give you all the codes. Thank you so much.

 

My car used to get the shakes and i tried everything to resolve it. Cleaning the throttle body helped and checking the intake air filter hose for cracks which mine had helped but what really did the trick was a bottle of BG44 in the fuel tank. After a few hundred miles it sorted the shakes out and the rough idle

 

OK, I've got some codes. It produced 3 different codes. P0307, P1316, and P1000.

 

I noticed your car is a '98 my. Have you ever replaced the timing chain and tensioners? This was a known problem for 4.0 V8 prior to late 2000 build.

 

Check the tensioners for the timing chain between the intake cam and exhaust cam. If it is orange, plastic, do not even start the car without changing it to the third design that is metal. I put an extensive write up on changing that tensioner and it is under sticky.

It they are still plastic and fail completely, and they will,l goodby engine. Minimum is remove head replace bent valves and maybe dinged piston.

This is serious stuff. I replaced mine at 42K miles. A must do. Don't start the engine until you check by removing the cam covers on both sides. Starting the engine puts a bad jerk load on the tensioners and that is where failure will probably happen.

 

The new tensioners I just got to replace mine with are 4th gen style. So even the metal ones have been redesigned a bit.
But yes those codes could mean bad tensioners. Could also be a bad coil, plug or injector. Even if the problem is one of those items the tensioners need to be dealt with and replaced if plastic especially with the miles on that car. Its been on borrowed time if they are still plastic. Mine failed at just 57k miles and took out 2 exhaust valves. 40k later I am replacing them again because the dealer may have put plastic ones back in. I may get lucky and find they are already metal but I need the piece of mind knowing they are not plastic.
I would try swapping the coil from that cylinder with another and see if the 307 code changes to the other cylinder. Also check for oil or water in the spark plug wells,
Then pull a cam cover and examine the tensioners unless you know for sure they have been replaced with metal types already.





Dave

 

I am at a loss for even where to begin. I have worked on my own cars, but never a Jag. I not afraid to try it, but not sure where to start. Any recommended reference materials?

 

The stickies at the top of this forum go over changing the tensioners.

I would take the valve covers off and check the tensioners and change them if they are not metal. If the tensioners are plastic you should also turn the engine until the cam flats line up to be sure one of the upper chains didn't skip a tooth which will cause rough idle. Then you can realign them when installing the new metal tensioners.
If it turns out the tensioners are already metal and ok then when you put it back together swap the coils and plugs as they had to come off to get the covers off anyways. Then check the codes again and see if the 307 changed to a different cylinder. if so then its a coil or plug.


Dave

 

Great now that you have the codes the P307 #7 misfire, P1316 Misfire refer to P1313 Misfire rate catalyst damage. Causes could be from low compression, fuel or spark plug / coil failure along with a few other things. The P1000 is an onboard diagnostic test and for now you do not need to concern yourself with this.

For the codes you now have I would pull the #7 coil and look and see if you see oil in with the sparkplug if not then swap that coil with another coil in that side. Clear your codes and start the car and see if the code changes to another cylinder and if it does replace the coil if not check the sparkplug.

As for checking the tensioners I would suggest that you do that unless you have documentation that they have been replaced with the upgraded metal tensioners.

For right now go with the codes that you have and see what takes place Do not concern yourself with the fuel trims just yet lets see what takes place.

Link http://www.jagrepair.com/images/Auto...%201997-99.pdf

 

Here you go!!

https://www.jaguarforums.com/forum/x...ics-how-52653/

 

Well, I took it apart today to Check the coils. I am still confused as to cylinder numbering on my '98. Standing in front of the car looking toward the back of the car, I first took the coil cover off the bank to the right. The two cylinders in the middle,( I think #6 & #7) had a significant amount of oil in the spark plug tubes. When I insert the plug socket, there was about 2 inches of oil up the side of the socket. I cleaned that all out before removing the plugs. I replaced all spark plugs on both banks. I switched the coils on 6&7 or the two cylinders in the center of the right bank. I then put it back together. Put the code reader on it. Cleared the existing codes and rechecked. The car is still running very rough at idle. However, the misfire codes are gone. The only code showing is P1000. I did not remove the cam covers yet, so I'm not sure about the tensioners. I figured I would do the simplest first. I'm concerned about the oil in those two tubes. All others were dry as a bone. Could that be from a bad cam cover gasket? Any help appreciated. Thanks.