i have a 1994 civic LX. when i start it in the mornings or when the engine has to warm up it kind of "pulses" sounds like it goes from about 500 rpm to 1000 and back down etc. until it's warm. i was thinking it might be the idle sensor? any ideas? has anyone experienced this?

 

If your car has an IAC Valve remove it and clean it with throttle cleaner. There are prone to carbon deposits making the motor shaft stick.

 

There is no "idle sensor". It is the Idle Air Control Valve, or Honda calls it the Electronic Air Control Valve. Like the other poster said, they get dirty and sticky. First though check that the radiator is completely full. Being low on coolant can cause inconsistent idling. Check in the radiator itself when the engine is cold. Don't just look in the plastic tank and assume the system is full.

 

alright i'll do that, where is the idle air control valve located?

 

On the back of the intake manifold near the throttle body. It has two small hoses with coolant and a 2-wire electrical plug.

 

I can't seem to get it off, did you just use pliers and a rachet? Did you remove the intake manifold to do it?