Hey guys, got a '97 with ~170K miles on it. Two weeks ago it stalled after an hour of highway driving, after getting off an exit and stopping. This week it happened again, but not right away -- on the first stop the car was unresponsive to the gas pedal for a couple of seconds, on the next stop it stalled. After stalling, I waited 10-15 seconds and it restarted with no problem.

My guess is that this has something to do with the EGR system, but I'm not sure that such a problem could actually cause a stall.

3 months ago I got a P0105 (Absolute Pressure Sensor) code, which I've left unresolved so far, and after the first stall I also got a pending P0400 (EGR Flow 'A').

I replaced the MAF sensor about a year ago (after it went bonkers), and cleaned out the usually-problematic EGR tube about 6 months ago (it wasn't too dirty).

I've checked some of the EGR vacuum hoses for leaks, but so far have found nothing. I've yet to test the actual EGR valve (original) or the solenoid (replaced 3 years ago), but I'm not sure this is the right direction to look as I'm not sure an EGR problem could actually stall the engine, although the fact that it happens after extended highway driving does point in that direction.

What do you guys think? What could this be? What should I look for? Is there anything I've obviously overlooked?

 

TPS issue ...

 

That will be easy enough to test, but this diagnosis doesn't feel right to me. This problem is only coming up after >1hr highway driving (~20 min hasn't triggered it, nor has street driving), whereas 2 out of 4 long highway drives ended in a stall after stopping. I'll check the TPS, but for now I remain skeptical.

 

I had to do the TPS on mine about 6 months ago. It wouldn't stall but it would randomly run like like crap (surging while cruising, bogging when taking off from lights and so on) and replacing the TPS fixed it. Haven't had the issue since.

 

Vacuum leak and TPS are first things I'd look at.

 

Ok, I'll be checking the TPS along with some EGR stuff. Will update this thread with results. Thanks guys.

 

Started digging around today, and I noticed the small vaccum hose on the bottom of the throttle assembly (the one connecting the EGR solenoid and the little hole at the edge of the throttle leaf) was torn. I'll replace it later today and see how things go. I wonder if that was enough to cause this problem, or if I'll need to keep looking...

 

even a tiny vacuum leak on these cars makes em run like crap

 

I haven't had a long highway drive on it yet, but so far so good -- and it seems like it's idling smoother, too. maybe it's just my mind playing tricks, but time will tell.

 

Drove around some more today... The issue is still here. However, it doesn't stall anymore -- it got close, but then surged and recovered. I did also notice that before this happened (as it did before, after highway driving) the gas seemed less responsive. It also came close to stalling (without bucking or surging) after a drive, then two hours' rest. I guess this could still be the TPS... or possibly the (recently replaced) MAF? I don't think I can actually test either of these parts for sporadic failures.

I could grab a used TPS off of ebay, and swap and see...

 

You need to do your TPS testing and TPS adjustment after the sensor has been brought to the engines full operating temperature.

Heat increases resistance. I'm thinking that your symptom occurs after a drive due to a hot TPS.

Not that the heat is the issue but you may not be experiencing the malfunction until things are fully heated.

Test it when it's hot and adjust it accordingly.

The MAF actually could the issue as well.

I previously experienced a sudden RPM drop (down to ~ 200 RPM) nearing a stall and then recovery. This would happen after about 5 minutes of run time.

Changing out the MAF remedied my issue.

 

Also, grab a can of carb cleaner and spray around all the vacuum tubes and around all gaskets. If the car surges, you found a leak.

 

Did that already, no leaks found.

 

So I replaced the TPS earlier today. The AT seems to shift more smoothly, and no issues so far.

I got curious and took apart the old (OEM) TPS:




high-resolution

Looks like one side got entirely stripped, but maybe that's part of the redundant design. Thoughts?

 

Dont waste your time chasing the egr that isnt the cause of the stalling for sure ive deleted the egr off all of my maximas. The car will run fine with or with out it.Looks like you may have found your issue good luck

 

Well, it wasn't the TPS. Another ride today, 2 hours there, 2 hours back. The ride there was smooth, the ride back stalled at a toll booth, and was kind of jittery for a minute, also with some transient power loss.

So all things considered, I think the next thing to check out is the MAF. Those jitters felt very MAFfy... I had replaced it about a year ago, bought one from a guy here on the org ( maxfever1987 ). Wonder if he'd like to have a warranty service...

 

I'm having close to the same issue with my 99 gxe . I'm thinkinh the coil packs might be the solution to both our issues

 

Things to look at/diagnose/test are: FPR and MAF

 

it seems that the newbies solution to everything is always coils and spark plugs.

 

True! Especially us 99 owners

 

Fuel Pressure

 

Grabbed a new (aftermarket) MAF - a Delphi from RockAuto, and after 1 long drive, so far so good. I'll update this when I do some more driving to confirm.

 

I tested the fpr checked out clean maf did not check that yet . thanks big wiz

 

A week and some driving later, no stalls or engine sputters, so it looks like it was the MAF after all. Like the last time for me, there was no code thrown for this part.

(However, now I've got a voltage problem, which is a whole other thing to deal with...)