1992 Q45 starts stuttering after it is warm

[wjmoore123]

I have had the car for about two months it has 170k miles on it and I have put about 4k miles on it. When I first got it it got really bad mileage. I cleaned the MAF and it then got around twenty on the highway so I thought it was good the last couple days it is fine to drive somewhere when it is cold but if I shut it off and then restart it the only way I can keep it running in town and at stoplights is to feather the gas and that doesn't always work when I get it out on the interstate it seems to do OK but it does stutter occasionally I have done some searching on here and it seems that it is either a bad MAF or a bad TPI or a bad fuel pump wondering if any of you have any further diagnostics that I can do so I don't have to swap out parts that might be good.
Thanks in advance Weston

[speedeast]

Start with free maintenance, such as cleaning out your IACV (carb cleaner works pretty good). Does it sound like it's choking out or it's just idling to low?

[wjmoore123]

no definitely choking out when I restart it it jumps up to 1000 rpm and then back to 0 unless I catch it just right with the pedal

[ericthered]

Simple check: measure resistance of fuel injectors.... when cold AND when hot (10 minutes after stopping the car).
Should all be under 14 ohms... and if the change from cold to hot is over 2 ohms, it might be bad now, and will be bad later.

It takes 10 minutes to do this - so just do it.

[ericthered]

The next thing to check (beyond cleaning the MAF) is cleaning the IAC. If adjusting the IAC doesn't seem to work, it definatly needs to be cleaned. Usually you kill the gasket when cleaning it, so have a new one on hand, or be prepared to jury rig. It has been a while since I looked at mine, and I always had a spare gasket on hand, so I am not sure if form-a-gasket will actually work in this application.

The IAC (idle Air Control) is in the back middle by the firewall. I think it may go by other names, too. But it is a cheap fix if that is your problem.

[wjmoore123]

I have narrowed it down to the MAF I cleaned it and straightened the pins that make the connections on the inside. The car is running good again with no problems but I fear it may be short lived so I am looking to buy a new MAF. I was wondering if anyone has had any experience with OnlyMAF on ebay they are selling a new aftermarket MAF for 89.95

[OwnerCS]

Where are you located? Are there any salvage yards in your area that have a Q45?

I collect MAFs from salvage yards from Maximas and I30s for those cars.
In my area, I haven't seen a 90-93 model with a salvagable MAF.

I have managed to pick up two good MAFs from Maximas for $35 each. The only bad one that I brought home and had to return was an aftermarket MAF. I like to keep a working spare MAF around just in case one fails.

Unfortunately, a new OEM MAF runs $478.24. Possibly some other members have experience with aftermarket MAFs.

[Q451990]

No experience with aftermarket MAFs, or any that I've heard of. I can get salvage yard ones all day for the 90-95... if tightening the pins helped, that was probably your problem - and you have a good chance of your fix being a reliable one. That is a common issue and common solution.

Good luck!

Heath

[kevindanielk]

I've seen many Nissan Maxima MAFs fail from cold solder joints, right where the plug pins actually solder into the MAF circuit board. Those bad solder joints start to really expand as the car heats up and when the electrical connection is broken, the vehicle starts to sputter and run like crap, as you try accelerating, since the ecu doesn't get a signal from the MAF to speed up the injector pulses. The engine is flooded with too much air from the open throttle plate and not enough gas. That was the problem with my Q when I first got her. It was sputtering and shutting off on me. My Qs MAF re-soldering was done in 2006 and it's still working to this day.
If you're handy with a soldering iron, I fix them by cutting out the seal on the square plastic cap piece, that's siliconed on above the circuit board, carefully using a single sided blade. I then remove the entire MAF circuit board from it's housing, re-solder those pins back onto the MAF circuit board, re-assemble the MAF, seal up the cap with some silicone and it has always worked. Something to consider doing since I have yet to see a MAF circuit board actually burn out or go bad, aside from those bad solder joints, most likely due to years of engine vibrations.
BTW, this is the first time I've shared this MAF repair info with anyone on any forum so use it wisely here on Nico.
I have seen local guys on Craigslist selling MAFs and requiring your old one as a "core"..... most likely so they can re-solder and resell them over and over. What else would they need a MAF core for :-(}
I hope this info helps you fix your Q.

[Q451990]

I've had success with the same method... If tightening the pins on the connector fixed it (in this case) I wouldn't go messing around with the circuit board yet though.

Heath