my 93 dx w/b16a engine has an idle that keeps going up and down from 1000 to about 1500. why is it doing that?

 

try to clean iacv, replace fuel filter..etc.

 

maybe firing order

 

It all started when i cleaned the throttle body and replaced the gasket.

 

damn i hate that... officially everybody that i have known in the past like 3 years as soon as they get an aftermarket throttle body they have major idle problems... and on stock motors the effect seems to be even worse

 

not sure if this would really be the problem but for me my car idle from 1500 to 2000 reasoning being was because i was low on coolant. maybe you should check that

 

Sounds like a vaccuum leak, you may have installed the gasket backwards or you didn't cleanall the gasket materialoff the manifold and throttle body before replacing. Easy way to test for vaccuum leak is to put your hand over the throttle body while the engine is running and if it keeps running you got a vaccuum leak. Or you may have gotten the wrong gasket. There's two different styles, a larger one for TB's with a Fast Idle Thermo valve and a smaller one for TB with out a FITV.