engine stalling on '96 Maxima

[Hula]

Clogged fuel filter.....similar to a past problem I had. Think of a clogged artery and lowered fuel flow eventually leading to no passing. Perhaps the line running through the filter is getting plugged and at 250K, and that fuel filters are often not replaced in a timely fashion, this could be a problem.

[TTony]

Looks like vacuum leak

[D-3vil]

well, today the car pretty much stalled every time the engine got a chance to cool down (about 3 times in total). After the second time, the check engine light finally came on (hopefully not unrelated to this). I will get it read on Monday to find out more about this.

[D-3vil]

Thanks all for your help. This was a tricky one, with many possible causes.

I went to my mechanic today for diagnosis. They pulled 3 codes off the car:

(1) Engine coolant temp sensor 1 circuit
(2) Knock sensor 1 circuit bank 1
(3) MFR controlled aux emissions controls (exhaust gas recirculation (EGR) solenoid)

They suspect that the EGR solenoid is causing the stalling, but they will hook the car up to the real-time monitoring system tomorrow morning (so engine is cold upon start).

According to my own research, if EGR solenoid fails in open position or fails to close all the way, it results in rough idle, hesitation, and possible stalling (which were my symptoms). If it fails in closed position, detonation results, which may have set off the knock sensor alarm as well. I'm assuming the solenoid is sticky and takes longer to open / close than it should.

[DragonZealot]

You should try the cheap stuff first like the temp sensor before you jump into EGR (read $$$).

EGR does not open when idle. It only opens when cruising. You mentioned this stalling happens if you start the car and leave it idle.

[D-3vil]

You should try the cheap stuff first like the temp sensor before you jump into EGR (read $$$).

EGR does not open when idle. It only opens when cruising. You mentioned this stalling happens if you start the car and leave it idle.

I was quoted under $200 for the EGR repair job (if it turns out to be it)... i'm thinking of replacing the temp sensor at the same time.

The mechanic's shop did say they will double check whether the EGR is really faulty - it should show up during real-time monitoring tomorrow morning (hooking it up to the flight recorder -- thanks for the tip!)

Code #2 is apparently thrown in correlation with many other codes, so I'm assuming the knock sensor is fine for now... of course, only time will tell.