X308 rough start up

Hi guys I have a 1998 XJ8 (X308) that on start up revs to 2000 rpm then settles down to 1000 then down to 650/700 when warmed up. Usually after 2 to 3 minutes. I have engine oil sitting in the bottom of the intake housing just below the throttle body. The engine performs normally after it has reached working temperature. I have cleaned the MAF sensor and a fitted donor throttle body. Just wondering if anyone has had this happen and if so what did you do to fix it. Cheers, Kirweekid.

That’s what they do after battery disconnection.

Check the ecu has a live supply +12v and not loosing memory.

North American Jaguar info for you.
600-03am3 Part-Load Engine Breather.pdf (114.2 KB)

303-12 Elevated Idle Speed.pdf (23.1 KB)

Interesting. That table doesn’t show an idle of 2000 rpm though

Thanks for that Andyk. I have done a hard reset and tried a known donor ecu all to no avail. Still working on it though.

Thanks motorcarman, I have had both TSBs and followed through with the info previously. I’m going to try another part load breather as I am suspicious there may be a vacuum leak there.