Caballero

Firstly, this has stumped me so any help gratefully received! Recently, my '99 XJ has started to stall out, only when it reaches operating temperature. It'll idle perfectly happily up to that point (and even drive) but the moment it's up to temperature & being driven (under load) it'll start to splutter/cough & die. It won't even respond to attempts on the throttle to keep it going. It'll start again immediately, but then do the exact same thing the moment you try to go another 100 yards (so you limp it home by doing 100 yards at a time). At this point it may idle ok, or may not - i've had both.

I replaced the Throttle Postion Sensor a couple of years ago, but read somewhere (here I think!) that the aftermarket ones are terrible, so figured that may be the issue. Here's where it gets weird. I managed to get my hands on an OEM TPS (in the UK, so not that easy) and fitted it - and for two weeks, it worked a charm! Jeep was running better than ever, no sign of the issue.

Until yesterday.

Same thing has started happening again, and to my mind the idea that it's the failure of the newly fitted TPS seems unlikely (although it was a salvage part, so possible). I can't think what else it could be?! A Crankshaft Position Sensor likely wouldn't allow the car to start again straight away, a downstream O2 sensor likely wouldn't stall it out in the first place...so i'm at the end of my wits. Any help/suggestions/experience with the same would be amazing.

(it's worth mentioning that also a couple of years ago I had an issue with a mechanic poorly installing a new rad and getting coolant in the gearbox and the temperature spiking. However this was flushed and the gearbox seems to be running ok since that point, so I don't think they'll be related....? But worth mentioning in case there's a connection i'm not spotting).

Roler

Well, I wouldn't exclude the CPS

a bad CPS could actually very well do this- the fact it might be heat related and therefor shouldnt , as you stated, allow to immediately restart the car is only part of the equation.

The normal restart and idle but stalling when putting load on it - it's what mine did (both CPS and CAM ) and resolved after replacing them (individually).

If your CPS has never been changed, that would be on my list...

Ralph77

I am kinda with Roler on this one.
Kind of sounds like what was happening to me in my '00.
Except for one thing.
My Jeep would just stall.
No sputtering or whatnot.
Like you turned off the key.
Can read about my experience here:

https://www.cherokeeforum.com/f2/cut...riving-241745/

Caballero

Great, thanks - i'll change the CPS as it's a cheap part (even if a bit of a pain to get at) and see what happens. The thing I think is odd is that changing the TPS did fix the issue, albeit temporarily, so I was thinking it must be related to that. I wondered if the TPS connector (rather than the TPS itself) could be bad, but this also seems possibly unlikely.

Checking - for CAM, you mean the camshaft sensor? This was changed a couple of years ago so i'm hoping it's not that!

Caballero

Thanks Ralph - reading your thread this does sound very similar. I was under the impression that with a bad CPS the car wouldn't fire right back up when it had died, but seems it did with you as well. I'll give it a go!

Ralph77

If you are going to go for the CPS if at all possible buy a Mopar one.
Do not cheap out.
The forum is littered with folks saying to buy only Mopar sensors.
Also littered with people having problems, thinking it was the CPS, replaced it with an aftermarket one, still having the problem, and wondering why.
Cause they tell us the CPS is brand new when they post.
9 out ten times they don't tell us what brand they used and we have ask.
Sometimes it is like pulling teeth getting that info out of them.
Finally do, they break down and get a Mopar one, and magically.....
LOL.
Aftermarket can be hit or miss.
Cause you do get the guy or 2 here and there that bought the cheap AutoZone one and it was fine so......

Caballero

That's really good advice, thanks - funnily enough, I did the same with the TPS (bought cheap, bought twice) until I fitted the OEM one.
The issue I have is that i'm based in the UK so getting MOPAR parts is almost impossible as far as I can see - I usually buy from Rockauto (as i've got three American cars) and the below is all they list;

I've no idea how to tell one brand from another with these?! I'd tend to just buy the most expensive one and hope that's the best.