96 Pickup, KA24e stalls when warm

[DriftingisLame]

Hey guys, I've been working on a hardbody pickup for a little while and I've been having an issue with the idle stumbling and then dying mostly when hot.

When I got the car, another shop had replaced the Cap/rotor, plugs, fuel filter, and MAFS. One shop said it needed a motor and all 4 fuel injectors due to leaking injectors and low compression. Well I retested compression and found pretty consistant numbers around 165-170 psi across the board. When it got in it had a rich code, #3 injector wasnt clicking as consitantly as the others, so I replaced it. I took out the plugs and the o2 sensor that were covered in black soot. I cleaned the crap out of both of them and put them back in and everything got a lot better. Now I dont have a code but I still have a hot stalling issue.

Is there a common problem with these things that I should look into? I dont have a scan tool at the shop I'm working at so I cant check past codes. I am thinking about doing the o2 sensor next, the engine was run for a while being that rich and it could have fouled the o2.

Anyways, any helpful suggestions are appreciated.

Thanks!
-Max

[seang]

I have not had hot stalling issues with either of my D21's. Is your catalytic converter clogged up?

[DriftingisLame]

That could be a possibility, however, the engine does not lack power at speed at all. The only problems I have is at idle. Also, if the cat were clogged, the problem would likely occur all the time, and not just in specific conditions.

[seang]

The reason I ask is that when the catalytic converter went out on my friends Crown Vic, it would run fine until it got really hot (the converter), then the engine would act up and stall out until the converter cooled back down. That kind of got me off guard, too; and I can't say for sure that your issue is the same thing.

If you haven't already unplugged the downstream o2 sensor, go ahead and try that. It should not make your CEL come on (at least it didn't on my truck).

[DriftingisLame]

Thats crazy, I've never heard of that problem. I'll check it out though.

So what exactly is unplugging the downstream o2 sensor supposed to accomplish?

[seang]

If the cat is bad, then I guess unplugging the downstream sensor isn't going to do much but let the ECU ignore how badly the cat is working. I figured that if the truck ran better with it unplugged, than you would know that the ECU was compensating itself out of an idle--if that is even possible. There might be other factors at work, so I can't say for sure, just pulling things out of my a** at this point.

[DriftingisLame]

Ok, so the engine stalled on me a whole bunch when it was warming up, seemed like it didnt want to stay alive till it got a little warmer. It started to run fine and I couldnt reproduce the stall until it had been hot for a few minutes.

Confirmed the EGR is not opening at the wrong time.

Confirmed that the Cat is not clogged.

Talked to a nissan master tech I used to work with and he said it sounds like the distributor. Nothing in the manual about testing the distributor, except to replace it with a known good unit.

Time to make a gamble with a lot of money I guess.