RPM surging @ 1600

[rber]

Hi All
I have been working on my daughter's Maxima XE with a 3.0L V6. The problem we're experiencing related to engine idle. With the engine warmed up, if you bring the rpm up to ~ 1600 (in park) the engine rpm will surge up and down continuously until you either increase rpm out of the 1600 range or let it fall back below 1600. There are no engine codes. I have removed, cleaned and tested the IAV valve (all seems well with it) and replaced the TPS just to make sure it didn't have a dead spot in it but the problem remains. Any ideas anyone?

I was just out for a little drive again and noticed that in park from idle when you depress the gas pedal very slowly there is no smooth acceleration up to the 1600 rpm area. I goes from ~750 to maybe ~900 and then goes right up from there to 1600 without me depressing the pedal further. Then the surging starts and does not stop until you force the accelerator to the point where you reach about 3000 rpm.

[Kompresshun]

Welcome to NICOclub!

Is the check engine light on at all?

The 2000-2001 came with a different intake manifold and system than the previous years, which has a few different things about it. If the check engine light isn't on, then it could likely be something related to that.

You may also try picking up some MAF(Mass Air Flow) Cleaner and cleaning the MAF sensor.

[rber]

Thanks 4DSC

No, the light is not on and I have an OBDII scan tool which is also coming up with no codes. One of the next things I intend to do is check the intake and injectors for leaks. I am also going to visually check the operation of the IACV and measure the voltage going to it during the surging. I am also going to check the voltage output of the rev sensor. I will also clean the MAF too. I'll let you know how that all goes. Won't be for a couple of days though as am working nights so no time til Friday.

[NutriaforBreakfast]

On my car (95) you have to disconnect the Throttle Position Sensor, rev the engine up and down,
and then reconnect it. The computer has to "relearn"

Also I have cleaned the IACV as there was carbon stopping it from working

[NutriaforBreakfast]

Actually its the CONNECTOR for the TPS you disconnect

[rber]

Yes, i have done that procedure to reset idle after replacing TPS, thanks.