Hi all,

I quite often get the restricted performance light on the dash, usually when the engine is cold. I've just plugged an OBD in and it is reading pipedream errors - misfire on cylinders 1-4. Is this a symptom of restricted performance, or is it the other way around, the restricted performance is a symptom if the misfires?

Thanks,
David

 

Can you post the codes?

 

The codes are
P0301
P0302
P0303
P0304
P1316

 

OK, I had to look at your other posts to find you've got a 2000 XJ8 4.0 - well worth putting this in your signature as Graham + Norri advised. We also need the mileage.
What happens to the 'restricted performance' light - does it go out?
Here's the diagnostics from Jaguar.
With one bank misbehaving there is a possibility that it's the timing chain tensioners which can be very bad.
Unless you know the tensioners have been renewed you'll need to check them - there are dozens of posts on this forum (search on secondary tensioners)

 

Thanks for the replies, the warning light on the dashboard does go out of its own accord. I don't know if the tensioners have been done. Thanks again for the info

 

For multiple code errors with nothing else obviously wrong with the car, check the battery. As it fails it can confuse the ECU into thinking it is getting error messages and that will put the car into restricted performance.

That is what happened to me and a new battery cured all 'faults'.

 

Interesting, I've had lots of battery issues recently, and a battery check is on my todo list. Thanks again

 

Let us know if a new battery fixes it - the warning light going away suggests Delta's right.

 

1999 xj8 with 92K miles. Replace spark plugs and cleaned coils, added lithium grease to the pack and replace the spark plug boot. Used gloves to avoid soiling the electronics with human oils, and other crude that turns into varnish then carbon after cooking on the electrics - old medical electronic engineering recommendations where ambient temperature is high. At the same time added a K&N filter system and intake cooling system. Repaired a short in the oil wire (splice, solder, & heat shrink) Took it for a test run and observed that restriction performance light still reappears, but less intermittently. I believe I have a vacuum leak somewhere. But it did run like a bat out of hell! Will keep looking under the hood and would appreciate any hints for this.