i have a 94 si. and my car revs up then down then up and so on all on it own when its not warmed up. I heard its a commin problem with hondas. has anybody had this problem. and if so what did you do to fix it

 

I have the same problem with mine. I've just recently started looking into fixing it because it's starting to annoy me now. So far what I've found is that it is most likely a vacuum leak, with a bad IAC valve being almost as likely.

I do have a hiss coming from around my air filter. Is that normal, or could that be my leak?

 

Mine use to do that, it might be something to do with the intake or vacume line. Most intakes do have that hiss noise but mine quit when i got the turbo ... maybe cause i got all new intake pipes... i dono tho ya check for leaks around your intake and intake maifold

 

It's usually a vaccum leak or IAC valve. Mine also did it when my head gasket went.

 

i had the same thing when my TPS died. i had take a newer one off of a totaled civic @ school and put it on. as soon as i did that, it idled perfectly.

 

The AIC senses coolant then opens and closes the air intake at will. The TW sensor senses no coolant and then supplies current to the AIC. If in any time the coolant is not bleed properly, the sensing system is thrown out of whack. Once the thermostat opens coolant flow is steady.


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