** X-Type stutter/jittering PLEASE HELP! **

[X_Type_South_Africa]

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.

:) :)
 

[Old Peter]

Hi Steve and welcome to the Club.

 

I have read and mused on your post.

 

You appear to have done a few things to solve the problem and I am wondering if it is a fuel problem that has not come to light.

 

I come from the carburettor era and if the car had one I would have taken it off and cleaned it. So have you checked the fuel injectors? Other than that, juggle the coils around, as you suggested.

 

Regards,

 

Peter. 

[X_Type_South_Africa]

Hi Steve and welcome to the Club.

 

I have read and mused on your post.

 

You appear to have done a few things to solve the problem and I am wondering if it is a fuel problem that has not come to light.

 

I come from the carburettor era and if the car had one I would have taken it off and cleaned it. So have you checked the fuel injectors? Other than that, juggle the coils around, as you suggested.

 

Regards,

 

Peter. 

Hi Peter, thank your for your response.

 

It could be a possibility and suspected the same when the issue first appeared, and have since replaced the fuel filter.

 

I will definitely do what you say and check the injectors.

 

Regards

Steve

[X_Type_South_Africa]

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!