Hi all,

I think I put this in the wrong forum originally....

Been driving an '04 XJ8 VDP for about a year now with no issues. This last trip i started experiencing an issue with a hot engine start (after driving for several miles, stopping for a bio break and re-starting). The engine idles very rough and sometimes stalls forcing several re-start attempts before she idles smooth. After this little dance of re-starts, it runs just fine for as long I drive it. If I let it sit for a while til the engine cools off, it starts just fine. A quick check with my OBD II reader it shows several coil misfires - random order each time. What could be causing such a crazy issue? Any suggestions? Thanks for any and all help.

 

strokez,

there are a couple of TSB's related to hot restart issues.


here's from another post:

Not sure if it is relevant to your situation but there was a TSB issued for the 2006-2009 4.2 X350 titled '4.2L NA Hot-Soak Re-Start Issues' (JTB00268).

'The customer may report a rough engine start or stall following hot soak of 20 to 30 minutes.'

The issue was caused by 'Fuelling calibration not robust for the market winter blend 10% ethanol fuel.'

The fix was to update the ECU firmware."

AND

There is a TSB related to rough start setting misfire codes, and lean codes, that leads to an injector cleaning procedure. Of course, none of these cars set a single lean code, and all have long term fuel trim within spec. There are very few TSBs relate to the engine on the 4.2 L vehicles, and the TSB came out in 2005, so I'm sure while these cars were still receiving service from the dealer they had fuel injection cleaning done as per the required maintenance. "

so if it came out in 2005, that TSB should be for the earlier 350's.


Hope that helps.

 

Thanks for that bit of info rosskuhns!

I did check the plugs and they are still in very good shape. The car has only 28k on it and it was (believe it or not) regularly serviced by the PO.

I will double check the ECU update with the local dealer.

 

winter fuel and warm weather not a good combo here in Houston and yes you need a ECU update

 

Had the ECU updated and no further issues noted. I find it hard to believe that they charge $150 for a download that is essentially Jaguars issue. Cost of ownership I suppose.

Thanks all for the help on this one.