I have a 01 nissan maxima with 123k the rpms rev up and the car makes a vroom noise then it goes back to normal. I went to a few shops some said it needs a new tranny others said it needs tranny flush and so on. My check engine just came on & autozone said it needs a idle air control valve which is why the rpms are racing up and reving. So obviously its not my tranny its the idle air control valve.. But what procedures are needed to fix this and what does it mess with if its not fixed asap. ALso someone says i need a transmission shift solenoid?

 

sounds like your idle air control valve is bad, you need to replace it ASAP as it may burn out your engine computer. The vroom noise you're describing might be a bad Mass Air Flow sensor, another common problem.

FYI, many times when the car sets manufacture diagnostic codes (check engine code i.e P1xx, etc.), the general code scanners will not give an accurate definition and many times point to transmission malfunction when in reality it has nothing to do with the transmission.
The best thing to do in this situation is get the codes that are read and look it up in the factory service manual.

GL.

 

I can't remember if the IAC valve comes with a gasket, but double check. You definitely want to replace the gasket with a new valve.

You may need to do the idle learn procedure after replacing the valve.