bad idle

jmfasc

Registered User
ok, this 89 sc i bought doesnt idle good when first started and after restart when its warm.it will die unless given gas,but after about 30secs it will idle on its own,but its a kinda rough idle. and i thought the guy had some kinda cold air intake,but when i checked it out there was no filter.so that couldve been what started it,i guess.so any input to what it might be would be great.
 
well now it idles smooth, i found a bad hose.but it seems like it takes too long to rev up,and idle keeps goin from 1000rpm to around 700rpm and back,but slowly. any thoughts?
 
A few things to check....

First, check the Mass Air Flow sensor (MAFs) to see if the filaments are dirty. If the car was run without a filter, it is likely that you are not getting accurate readings. Second, check the Idle Air Control (IAC) motor. It could be sticking due to grundge from no filter as well. The throttlebody butterfly may also be sticking. You may want to tear down the complete air intake/ throttlebody system and clean it.
 
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