Ok once in a while when I turn on my 2002 Ford F-150 the RPM's go from 1000 to 800 then back to 1000 over and over and this is at idle. I haven't gone to get it looked at and I want to see if it's something I can fix at home. Anyone have any suggestions on what it can be?
I will keep my answers fairly simple, as the procedure will differ, and I'm unfamiliar with your vehicle.
Clean the MAF sensor. It is a very thin metal filament inside a circular component attached to the throttle body. It's purpose is to measure the volume of the incoming air.
Clean the throttle body. All the incoming air passes through the TB. While the air filter removes a large portion of material, some may get through and collect on the throttle body inlet which is a very small-holed screen.
Replace the idle air-control valve(IAC). The IAC controls the amount of air passed through to the engine base on information from the MAF and what is allowed through the TB. They're all intertwined.
Coincidentally, I will be doing all three personally, as my will car will not start until I give it gas. The battery powers the components, and the starter is initialized, but I have to get it some acceleration, so if anyone has a similar issue, try the methods mentioned above.
*some one let me know if I'm correct, I'm just answering to help cement what I know (or don't).
A vacuum leak after the MAF sensor could also cause this. I would do this before replacing any parts, since it doesn't cost anything (if you have some starter fluid lying around).
This YouTube video might be of use.