1996 XJ6, engine goes to 2000 rpm as soon as it is started, it idles rough and smoke. error code is P0727. Please help

 

OK, you are new, so WELCOME, the fun is about to begin.

Your XJ6, being a 1996, is what is known as an X300 model.

Fear not, you will get used to Jags weird model codes eventually.

Also, one of the MODERATORS lurking around here will PLEASE move this to the X300 area where you will get many, many answers for that issue.

Just noted you are not saying where in the world you are located. That is quite important with answers to any questions, as these cars do vary with different markets.

Once we all know what market car we are dealing with answers will flow.

Things like:
TPS
EGR system
Cat convertors
Vac leaks
Idle control valve
O2 sensors

All come to mind at a quick glance.

 

Thank you for your help, I will post my question at the X300 forum