Hello, i posted a thread about my jag with a over fueling problem some weeks ago now i have a updated problem can you help.

car will start and run, wont idle/tick over on its own needs me to apply my foot to the accelerater pedal and often cuts out. runs as if theres a missfire and soundlike its hit and miss like runing on 5 cylinders?, guessing the throttle body needs a clean and possibly a spark plug or maybe a coil? problem...........any one had this similar problem....any help is gratefull thanks...

Pleased i joined this now hd alot of help and made some good contacts.

 

Do you have a "Check Engine Light"? If so, you should have the codes reqad to determine the likely problem(s).

 

The plugs are cheap and easy, so that's usually a good place to start. Use Champion RC9YCC or RC12YCC.

 

I had a similar problem. Sometimes I would press the pedal back and forth to keep the car running to avoid stalling. Initially I thought it was the gas pump, but it turned out to be the crank position sensor. If the car is over 100k miles, they go bad as you can confirm in other posts. Also it's very easy to replace.

 

also check your tps and mechanical screw for the throttle body butterfly, it may need adjusting.

 

I would suggest also checking out the fuel pressure regulator. Easiest way is by substitution as they are very easy to replace and you can normally get one on ebay for about 15 pounds. (Tip - search for xj40 regulator - they tend to be cheaper and are the same).

(Note: Check the vac pipe to the regulator is not split before trying substitution)