92 Q45 stalling problem

[Q45hoarder]

Question...

My '92 Q45 stalls intermittently (when driving at speeds below 50MPH). Once I open her up on the highway, it runs awesome. I have to rev the engine at lower speeds to keep the engine going (pump the gas pedal multiple times). It boggs down like it's not getting fuel. I once fancied myself a pretty good Q45 mechanic, but this one got me perplexed. No obvious isues with the transmission, changes gears smoothly etc.

I've done everything I can think of relating to fuel & spark. Done the normal replacement stuff like spark plugs, fuel filter, fuel pump, fuel computer, fuel pump relay, checked all 8 injectors (w/engine stethoscope & ohm/resistance check-was good), checked fuel lines, etc. I've also checked all the vacuum hoses. Only stalls at lower speeds after its been running for over 10 minutes.

Would a faulty MAF sensor cause the above problem?? Any suggestions??

[goody90q45]

If you haven't already, clean any corrosion of the MAF sensor pins and MAF connector pins, tighten the connector pins (they should look like the middle pin in the pic), and lube both sets with dielectric grease. Do you have the metal clip on the MAF connector to hold it onto the MAF? Is the CEL on?

[Q45hoarder]

Tried that too. But I'll try switching the actual MAF sensor and see if that does the trick. Check Engine Light usually doesn't come untill the engine sputters all the way off.

[Lokim]

Test the coolant temp sensor. It sounds like it may not be registering higher temps, hence it behaving for the first 10 minutes when the ECU would be running the engine rich anyway...

[Q45hoarder]

Didn't even think of that, great idea! Will check that out next.

[OwnerCS]

I had a similar issue on the 99 I30 with an aftermarket MAF. I picked up an aftermarket MAF at one of the local salvage yards. So I brought it home and put it on the I30 to test it. All seemed to be fine for the first couple of days. A few days later this intermittent stalling problem started at stoplights. Some days it was worse than others. I put the original Nissan OEM MAF back in the and the stalling problem disappeared. I returned the bad MAF to the salvage yard and got a refund.

[Q45hoarder]

Yup, you guys were right! Bad MAF sensor connection. I made the mistake (earlier) of skipping the step where you apply electrical contact grease to the MAF connections. Greased the connections & PROBLEM FIXED!! No more stalling. This website ROCKS!! Thanks again guys...and Happy New Year! Mine's off to a great start.