When I start up my 1990 Accord Coupe it goes to 3000 RPM's and down to 1000 RPM's and then back to 3000 RPM's and it just does this over and over,so if you could help me with this proble that would be great.Thanks

 

IACV. Take it off, clean it, try it again. Problem contuniues, check the TPS. Those 2 sensors are what controls idle. Check aswell for any vacuum leaks. If you have a cracked/unplugged vacuum hose the idle will jump like crazy. A easy culprit for the F22 is the top mounted PCV valve gets bumped and it cracks, loosing any kind of vacuum seal. Happened to a friend with a 90 Accord Sedan.

 

Also check and clean FITV - fast idle thermo valve, right of the IACV on the Intake Manifold.
Might also be air pockets in the coolant - bleed + replace.

 

Make sure all vacume lines are secure too.