i have a 2001 XJ8 sport the engine management light has come on the fault says its missing on 2 cylinders i have changed the coil plugs for these cylinders and done a compression test which was ok (a little bit low on 1 but not by much)it has been into the main dealer twice and they have happily taken 1600 off me and did plenty of tests but cant find the problem i will try to find the list they have done and post it with this later has anyone any ideas what the problem may be?

i have a 2001 XJ8 sport the engine management light has come on the fault says its missing on 2 cylinders i have changed the coil plugs for these cylinders and done a compression test which was ok (a little bit low on 1 but not by much)it has been into the main dealer twice and they have happily taken 1600 off me and did plenty of tests but cant find the problem i will try to find the list they have done and post it with this later has anyone any ideas what the problem may be?

Hi if you can let me have the fault codes from the ECU, I may be able to give you some guidelines to get to the bottom of this. One question (don't take this the wrong way), but are you sure you changed the correct two coil packs, only asking as the cylinder numbring of these engines is not as straightforward as others and is also age dependant!

Hi Simon

I've had my XJ8 Sport for six years now. My engine management light comes on periodically as well. When tested, it says there is a problem with the left hand catalytic converter although all seems to be well.

A dealer friend of mine who is also a Jag nut (and who sold me mine) says the fault with the light is common-place and after having it checked over on three occasions, I've learned to live with it because after a couple of weeks/months, it goes out of its own accord.

In my case, I think I've traced the problem.

For the first four years of ownership, I only put branded fuel in. Since testing out BP Ultima 97-octane I attained 26.4mpg. For the return journey (Bath to Peterborough), all I could get with a tank verging on fumes, was Tesco's unleaded. Lo and behold, 28.4 mpg and the EML went out!

Make sure you put the car into Sport mode periodically and when the engine is at optimum temperature, give it a boot-full.

Yours

Nic James