Please help. Purchased an 04 XJ8 VP with 112k miles on it six weeks ago. When traveling up to 30mph drives great, over 70mph, not bad. The problems is once I hit 35mph and try to level off my speed, the engine searches for gas, whining and spinning, when I feed it gas, fine I can go up in speed but cannot level off in that range. When I set the cruise control, it lessens the effect a small amount but does not fix the problem. The tachometer flippers around 200RPM in this range.
I had an Aamco transmission shop fix an oil leak, new plugs, filters, etc... as well as hook up the vehicle to get all of the new codes/readings. They said everything looks pretty good. Discussed the problem with the mechanic who formerly serviced the car and he seemed dumbfounded.

I have gone on these forums, when I have seen someone posted a similar problem, there was never a follow up solution listed. Thanks for your advice, ANYONE!!

 

I gather from your post that the car is not throwing an error code on the dash that can be read an acted on by a competent Jag tech. So a few thoughts that come to mind in no particular order:

1. find a new Jag service tech. who won't be "dumfounded".
2. replace the fuel filter. Easy and cheep to do. Even Aamco can do it.
3. the car has 2 fuel pumps. One may be kaput. You will need some detective work here.

Not to put too fine a point on it, but a guy who tells you the codes are "pretty good" does not inspire confidence. He may be trying to tell you something like --- like take the car elsewhere. Seriously mh3, a few bucks extra, spent on a top drawer tech is money saved in the long run. I,m sure there are a number of them in South FL.

 

Hay MH3,

Any feedback yet on the resolution of your problem? I know you did not get much of a response, not typical I assure you, but there are a lot of dudes here interested in how you made out.

 

Thanks for checking back, Tarhealcracker.
I had a certified technician look over the vehicle. The only eyecatching situation was that the oxygen sensors did not respond to the diagnostic machine, no movement. All other tests achieved a positive response. I was quoted $ 110 a piece (x 4) for the sensors and $ 50 to install. He couldn't guarantee me this will do the trick but atleast it will take me one step closer. I can probably swing it next month and will follow up with a post afterwards. Thanks.

MH3