Nissan Repair: Nissan Maxima 2000, mass airflow sensor, nissan maxima

Question
QUESTION: "So i changed my IACV becuase my car would die when i turned it on unless i pressed on the gas pedal for about 5 mins to let the car warm up. So i got tired of doing that. Now when i turned on the car it stayed on but now the rpms jump back and forth  I been reading this might be to MAF sensor. Only thing is my car didnt do that before. So i bought a bottle of MAF cleaner and cleaned the sensor car started well everything seemed normal for about 1 min then the car started idleing crazy again like it did before i cleaned  the MAF. So then i got one from autozone it looked dirty only thing looked new was the panel with the screen  that it goes in. Once i installed it the car turns on but then it dies dosent stay on even if i try and give it gas. The MAF test i did to begin with was to turn the car on as it idled back and forth i unplugged the MAF sensor thing calmed down before the car died out. Thats why i believed it is the MAF, but like i said i put the one from autozone thinking my car would stay on but it didnt. I put the old one back on and it stays on but idles back and forth do i need to drive it so it settles down? Any advice?

ANSWER: Al,

Sounds like Autozone owes you a good mass airflow sensor as the one they gave you seems to be defective.  It sounds like you are on the right track since you did replace the sensor.  Before the sensor was replaced the car idles strange (up and down) and with the rebuilt unit it dies.  I would go with a different replacement if Autozone sells you another one that kills the car.  Also, check the intake hose from the mass airflow sensor to the throttle body and make sure there are no cracks, loose clamps or other places that unmetered air can get in the system.  Also, check the PCV as it might be sticking and that will do strange things to the idle.

---------- FOLLOW-UP ----------

QUESTION: I fixed my problem. Check this out 1)I replaced my IACV first it also came with the piston senor I guess you would say that has the plug for the harness connector. Being that it was new i figured swap old for new and am done right? Wrong when i cranked my car the RPMs went 3000 to 2000. I thought my MAF sensor went out also. Replaced that with one from Autozone now my car just cranked and died? So now I say put old MAF senor back on. Install the old piston sensor from bad IACV into new IACV. And lets see what happens. WHOLA car cranks fine and rpms stay at 1000 idleing. So just want to ask why do you think the new piston sensor on new IACV was making my RPMs jump eractically. Did the ECU have to be reprogrammed after install?  I took new MAF back for my money.  THanks for help spread the word.

Answer
Al,

On a 2000 the ECM does not need to be reprogrammed.  If the part was a little out of tolerance you might have had to go back to the original.  If you have not changed the coils on your car you might think about it since there was a service bulletin on them.