Hi, I hope someone will be able to give me some assistance with an issue I’ve been trying to resolve for a while. I have a 2008 model 3.0L V6 AWD X-Type with 150 000km (93 000miles) on the clock. I really love the car, and it’s the third Jag I’ve owned.
About a month ago I started noticing a jitter, stutter, jerk (whatever you want to call it) when traveling in the city between 50-70km/h (31-44mph), particularly when travelling uphill or with additional weight in the car, and I’ve had no warning lights appear on the dashboard. It doesn’t occur every time I drive the car, however when it does it seems that it occurs when I accelerate normally through the gears until I reach the lowest gear and lightly feather the accelerator at about 44mph. The stutter goes away as soon as I apply the break or accelerate more rapidly. Furthermore, occasionally a similar feeling occurs when accelerating from rest or close to rest, where it feels as if I’m applying and releasing the accelerator at a fast rate or am momentarily losing and regaining power, despite keeping the accelerator at the same level.
I serviced the car 3 weeks ago where the air, fuel and oil filters where replaced as well as the engine oil, and also had a diagnostic test run on the car at my local Jaguar dealer, and no error codes where reported. The issue wasn’t resolved. I found another local mechanic who works on Jaguars, who too ran a diagnostic on the car where a misfire in cylinder 3 was reported. They found a leak in an air pipe which was fixed and the error code went away, and all seemed fine, however the stutter wasn’t resolved. After taking the car for a ride to experience the feeling, the head service manager felt that it may be as a result of a misfire due to a faulty spark plug or ignition coil. I replaced all the spark plugs and bought one ignition coil and replaced it with the old one in cylinder #3, hoping the previous error code of a misfire in that cylinder was a hint. The problem is still there though; however there is no guarantee that the faulty coil (if that is the issue) is actually in cylinder #3. Should I shuffle the coil that I know works around in the various cylinders in the hope that I eventually find the faulty one and solve the problem?
Like I said it doesn’t always happen, however on occasions that it does, the stutter seems more exaggerated than the previous time, and other times it’s very mild; I don’t want to ignore it which may lead to something bigger. Any kind of advice or help would be greatly appreciated.

 

I'm having same sort of problem on my 2001 2.5 v6 petrol code reader gave fault code p1642 fuel pump monitor circuit high imput but looking through forum others suggest it could be the coils and plugs.

 

Try this: next time it stutters let it stutter until a code appears to see what system is failing(fuel, vacuum,ignition)Fuel: connect a scanner and see what the fuel pressure is when failing. Vacuum: check breather hose, Booster line for cracks, You may get a P0173/174 and should miss at Idle(high vacuum).Ignition: Depending on how much you want to do you can swap coils(if you get a code) to see if the fault follows. You can also check the coils OHMS and compare them for high/low variation(10% is ok) same with injectors.
You could have a dirty MASS AIR sensor or a TPS (throttle position sensor problem. Check the TPS by connection the scanner then ( key on / engine off) go to the TPS on the scanner then S L O W L Y depress peddle and watch the scale for a dead spot or a jump in reading. I have used all these to diagnose my problems and avoided needless parts replacement.Time consuming yes but I have saved $100s and was satisfying. Good luck!

 

i had what i called a shudder , felt like someone randomly and quickly tapping the brakes on me. i had learned from other cars that this COULD be a misfire.

Common thought was i probbly had oil leaking into my spark plug wells ,

so i purchased:

6 new platinum plugs
6 new coil packs
1 set valve cover gasket
1 set manifold gasket

I stripped the car down and when i could see all 6 plugs i noticed the plug wells were bone dry. So rather than diving into that valve covers i installed plugs , coil packs, cleaned MAF sensor ,new air filter and soaked the pcv valve in carb cleaner.

The car had 90,000 when i did all this and i purchased it at 86,000. All i can say is what a difference these made in the driveability of the car . it is so much smoother on take off , instant acceleration and the shudder is gone.

I would also like to add the car was throwing NO codes.

 

Thanks to everyone for all your assistance. Shortly after creating this thread I solved the problem, however wanted to wait a few weeks to make sure the problem was truly solved.

A few days before the shudder began, I added a fuel additive to my petrol tank after filling up, which I suspect may have cleared any dirt and debris in the fuel system, however clogged an injector at the same time. As a last resort, I added a strong mixture of injector cleaner, which has solved the problem! The car is running like a dream, and had I known that this would be the cure in the beginning, it would have saved me a heck load of money!

 

Ok dude well it's hard not seeing it but does it make a clunk or bang noise when this happens?

 

What brand injector cleaner did you use?
Mine will do this on occasion, my fix has been to drag race it per say.
I hit the on ramp to the highway and then hold it to the floor till I hit 70mph.
Call it the poor mans injector cleaner, O2 cleaner etc etc.

But if the cleaner you used does work I would like to try it.