Corolla Idling problem

[MarkIIRx12]

Hi

im working on a 1994 corolla with 4afe.

the car runs fine when driving, but it has a very strange idling problem, it keeps going from 1000-500rpms, up and down all the time.

i tried checking for errorcodes, but there is no codes stored.

anyone have a clue what causes this to happen?

Thanks for ur answers

[celica_john]

Does turning the aircon on or off fix the problem?

[MarkIIRx12]

Hi

the car doesnt have a ac, so i dont know, but if i put in gear and drive around on idle, the idle seems normal, so it seems to happen only when its idleing without any load on the engine.

[Cuzzo]

Does this only happen at idle or when driving too?

If both you probably want to burp/get all the air out of the cooling system.

[MarkIIRx12]

Hi

the car drives fine, it happens when its idling, doesnt seem to matter if the engine is hot or cold, it just keeps jumping up and down on the rpms.

it shouldnt be any air in the cooling system since the car was fine before, it still has all the water and nothing have been done to the cooling system, so i think its strange if it suddenly got air in there. but i will watch again if its losing water or other funny stuff

[Hiro]

Check you don't have a vacuum leak, and give the throttle body a good cleanout.