Rough Idling Problem

[Mario In WV]

Yes, i'm back again! sorry i only come here when there's a problem. seems like a cool forum. anyway, my question is that i went out today in my 1990 corolla and everything seemed ok, until my way home. when i came to the last stop light, it started idling real hard...like the engine was shaking and it almost cut off. but it rides ok and when i pulled into my parkin lot and stopped to put in in reverse to back up it didnt do it. i have put in a thing of that carb and fuel injec. cleaner like a month or so ago. and a neighbor suggested something called Heet??? but i'm afraid it mightbe something more complicated...hopefully not, but u know....any help/suggestions would be appreciated. and i hope i was clear. thanks!

[zythr]

Could you be more specific?

[ktownkrolla]

ironically the same thing happened to me today too. idk if you have a 4af or 4afe engine but i had to turn the idle up on mine to get it to idle normal again. i know that there is a bigger underlying problem than that, like maybe a bad idle air control valve. but it seemed to be a temporary fix to me.

[Donald]

Take off your intake tube, open the throttle and take a look inside the intake manifold. If it is all gunked up with carbon, you might need to clean the intake and more importantly, the throttle body. Some aerosol carb/choke cleaner should get most of that crap out.
Do all the passages and orfices in the throttle body, especially the idle air control passages.

After spraying that stuff inside, the engine will be hard to start, and will smoke and run rough for a while, but that is normal. It will clear up in a minute or so.

Best if you do it in steps, spray a little, run it for a while, spray again, run for a while. That way you don't run the risk of hydraulic lock (so much liquid in a cylinder that it locks up)