2001 S-Type 4.0L Sport

I have a problem where my Jag misfires at around 40mph and it idles rough. I have changed plugs and coil packs but the misfire still happens. What can I try next??

 

Welcome to the forum jaguar258,

I've moved your question from UK & Eire Region to S-Type forum. This is the place to post technical questions about your model.

Please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some information about yourself and your vehicle for all members to see. In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Might be timing - have you changed the tensioners etc? Your engine is on borrowed time if not

Or maybe an air leak - use OBD live data to look at fuel trims.

 

Did you find oil in the spark plug wells when your replaced the spark plugs and coil units? If so, the cam cover gasket(s) and spark plug seal(s) are leaking and must be replaced.

Is the MIL on and are there any DTCs stored? If so, post them here.

 

my Jag Misfire about every other week,had plugs and coils change