Jaguar Xk8 1998 . New plugs . rough idle when cold ,and rough running after hard acceleration . Engine code for lean left bank ,cleared then returned with in a day . What may be the cause ?

 

Lean would say good plugs and complete combustion . So you can check that off . Look for the ECU to relearn the long term fuel trim after certain targets like RPM and time to be satisfied .

 

Possibly poor spelling in the title?

 

Welcome to the forum wizzy,

When asking a question like this, always post the actual code(s) to get the best advice.

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

 

sounds like intake air leaks after the mass airflow sensor. fuel trims will indicate this condition. check your breather hose and other engine air seals.