revving engine

[Daly]

I know I asked this once before but can't find old thread.
When in park my engine is revving up and down, 1000rpm-3,000 rpm
What part needs to be replaced?
Thanks

[Y33TREKker]

I know I asked this once before but can't find old thread.
When in park my engine is revving up and down, 1000rpm-3,000 rpm
What part needs to be replaced?
Thanks
Maybe your IAC (idle air control) valve needs replaced? Or simply cleaned.

[KRemo]

My VX did it and nobody could figure it out. I replaced idle air control and kind of worked but started again. finally I replaced the idle air control wiring and it fixed the issue.

[89Vette]

Vacuum leaks (intake manifold leaks) often cause this too...but you should be seeing a code for that.

[VxSport]

you should also see a code on the IAC too. I had a simular revving problem (not as high in rpm's). The code ran was for the IAC, I replaced it, cleaned wirring pigtail, also cleaned the entire air intake and MAF at the same time. Very little fluctuation in the rpm's since, except when the A/C kicks on.

Hope this helps too.