Hello, i just picked a 90 accord for 100 bucks. Not perfect but I like it. Anyways, I'm having a problem with the idle. It jumps between 1000, and 2500 RPM ( 1500 when warm ) in an up down up down up down fashion. Runs fine otherwise. I replaced the whole throttle body and that sensor mounted to it ( TPS? ) with one from the junkyard. No help. Anyone have any ideas? Im not too familiar with hondas yet.

 

I should add that it throws the TPS and injector codes. But only SOMETIMES. Sometimes the SES light never comes on, even though it still idles bad.

 

Sounds like you have a vacuum leak... I gave an explanation of how I find them in another post but I suppose I can post it again. Take a small blow torch and open the gas but don't light it... then just run it by all the tubes with the engine on and if the engine starts revving higher when the gas is over a certain spot, you have a vacuum leak!

 

Just tried that. No luck. Heres a video to better describe the problem...

http://smg.photobucket.com/albums/v6...nt=idle001.flv

???

 

Check throttle... it might not be working too well (may need oiling)

 

well, after seeing the video, i do believe that you are not getting as much oxygen into the engine as you should. look for a vacuum leak. use a tissue and rum it around the throttle (never let it go!) and check all the hoses. good luck!

 

Ended up being air in the cooling system tricking the cold idle valve. Thanks all!

 

Pee Wee ... how did you find that ... Ijust bought myself a 90 accord and has all sorts of rough idle ...