Hello all,

I've got an 01 XJ with around 265k miles on it. I am having issues with it stalling, both in park and drive. It's got a rough shakey idle, which it's idle was never smooth but I notice now it tends to randomly shake at idle. Temps are good, battery connections and voltage is good. I've noticed occasionally on the highway it'll give a little jerk, but that is occasional. However, it never fails to stall if I let it idle for a few minutes such as traffic, in a drive thru, or when I just let it sit in my driveway. I cleaned TPS, IAC and throttle body. Replaced MAP two weeks ago, still have all the symptoms. Also, cam and crank sensor were replaced two years ago with AC Delco sensors. Fuel pump was also replaced around March this year. Any advice would be appreciated on what it may be.

 

Well, for starters,. don't trust those things. Aftermarket sensors on these things, especially those two, are famous for being really poor, ranging from dead out of the box to only lasting weeks, months, or a few years. So, don't rule those out as possible causes. But, they usually don't cause idle problems. More like "won't start or won't run" problems.

That said, does it show any codes? You can have codes pulled at AutoZone for free. Very useful. Do that and post the results here.

Other possible causes are your plus or coil packs, or a vacuum leak. Lots of good videos on YouTube about how to find vacuum leaks.

 

I have two scanners of my own, all I've got is an evap leak that I've had for three years which autozone also pulled. Coil pack and plugs were also replaced two years ago. I havent thoroughly checked for vacuum leaks but did a quick spray over the engine with brake parts cleaner and didn't get a response. Tps and iac seem like they might be the problem since you said cam and crank typically was for the no start. I know that when my crank sensor went bad, it stalled out similarly to how its been but never turned back on. My xj tends to start everytime it stalls except for once where I had to let it sit for 5 minutes.

 

TPS is easy to test, and the aftermarket stuff is not particularly good. IAC can sometimes be cleaned. Both are easy.

 

What rpms do you have at idle?

When was the last time you cleaned the TB? Don't forget the IAC channel if you clean your TB.

 

THIS^^^^^