1998 XJ8 95k

For the past 2 months or so the car actually stalls out at an idle. Right when the fan shrouds are to kick on the car drops in rpms, and has a hard time coming back up. Sometimes it dies and stalls out, and sometimes even worse when it tries to revive itself before the stall it shoots into stability control fault and freaks out and bounces around at 1500-2k rpms.

You can turn it off and turn it back on and usually it goes away and the car functions normally (leads me to believe it's CPU related), but lately it has stayed on even after turning it off and turning it on. It DOES NOT do this all the time, the weather is not a matter either i've found out it's been hot and cold. This is all in Drive at an idle in the driveway.

I've had the throttle body cleaned completely before, yet the car has this weird shifting pattern sometimes (it's almost daily now) in both sport and normal mode, (perhaps computer like I said) where it will stay in gear and actually engine break itself a lot and shift at the wrong times jolting the car forwards and staying at 1k rpm at a full stop (no good and unsafe really). It's not the transmission itself obviously right as the car will function normally if you turn if off and turn it on usually.

I also noticed that when I start the car (even in warm weather) after it sits like 5hrs it will stay at 1200rpms for about 20 seconds. It used to only do this in the cold weather, now it does it all the time at cold start.

*EDIT - Restarted the computer and it disappeared of course, drove it for a while today and it didn't give one symptom. These models are a total joke unfortunately ; \

 

haha I kinda figured nobody would know what's up on here but was worth a shot. Either way I think it's time for this money pit x308 to get the boot in a couple months hehe. Bought in Feb 08 for $8888 with only 77500 and ended up paying about $6k in repairs in just 3 years hah.. and that's using a local mechanic and cheap online parts haha... I feel sorry for folks that are just now buying these things!

 

that's happening alot lately, check your brethren in this sub-section and in the XK8 area (same engine setup) for some ideas on where to look. Those intermittent issues are a PITA for sure. g'luck, or sell and clear your conscience

 

Sounds more like you want an excuse to get rid of it...

Do you ever get the check engine light illuminated? If so, have you pulled the codes to see what they might lead to?

1st thing I'd suggest is to clean the Throttle Position Sensor (TPS) connector (right side of throttle body). Many of the idle speed, surging, etc., symptoms you describe are similar to what I've seen when the TPS connector gets corrosion between it's dissimilar metal (gold in TPS body, tin in mating connector) pins. Simply unplug, clean with some contact cleaner/lubicant and reconnect. This takes only about five minutes, it always clears up my strange throttle related issues and the fix lasts for 6-8 months.

If this gets rid of some of your symptoms, great - should make isolating others easier.

 

Hah not quite, sold the POS for more than I had expected around here. I suggest all you guys do, get an 05+ if you want the real thing, x350 too much junk all around. Goodluck!