I just had a brand new problem with my 120K 05 XJ8L. Suddenly ran rough at idle, wouldn't restart in parking lot, flat-bedded to workshop, fired right up. Replaced original equipment fuel filter, drove 20 miles & same syndrome occurred. After a few minutes of frustration, started up and drove, but NOW has a clear transmission-related symptom. I can hear the transmission whine as I come down to a stop, and there is a slight kick as it downshifts into first, or maybe it's the torque converter de-clutching.

Plugged in scanner, codes for misfires, nothing else. Leaks from transmission cooler lines have yet to be repaired, but didn't seem excessive.

Anyone have drivability problems connected to low ATF? My lift is disassembled for workshop move, so I've parked the car, probably until February.

 

I’d tackle the misfire issue first. Misfires on these cars are known to cause the transmission to misbehave. Which misfire codes has it thrown, exactly?

Have you checked the fuel trims? This may help in diagnosing the problem.

Yes, low transmission fluid can cause your transmission to mis-shift. I don’t know how much it has been leaking, but I wouldn’t drive it intil you get the leak fixed and the fluid topped off. Speaking of which, has the transmission fluid ever been replaced?

You may have multiple problems that all cropped up at once, or could now be hearing and noticing things that were there before, but now are causing driveability issues.

 

+1

definitely fix any engine problems first and for the reason given.

 

I can't open or download any of the files. Says unknown format

 

Seek tech-savvy help.