Idle Problem

When the car is idleing, it ranges from 1000-3000 rpm's instead of the normal 900-1000. The car will rev up to 3000, and then drop to 1000, and then jump back up to 3000. I've already replaces the idle control valve, adn that changed nothing. I'm about to pull my hair out if I can't fix this..... 1993 Civic 1.5 16 valve LX 5 speed.

You should try and check your antifreeze...this happened to my boy and we adjusted his idle changed his o2 and all that...but then we noticed he was low on antifreeze and it stopped...(just a suggestion

I know it's not the antifreeze, cause the engine over heated the other day, adn we checked the water level and the antifreeze level. The 02 sensor is just about shot, and we just bought a new one (on the way) could it be the o2 sensor, or is there something mroe major going on?
This is seriously starting to hurt my wallets, so if someone could halp me quick!!

wow.i only have one wallet. you wouldn't happen to have a fuel pressure regulator would you? on mine, when i leave the hose off, the rpms will bounce up and down like that. if it by chance has a computer chip it'll do that on occasion. other than that, don't know

I know it's not the antifreeze, cause the engine over heated the other day, adn we checked the water level and the antifreeze level. The 02 sensor is just about shot, and we just bought a new one (on the way) could it be the o2 sensor, or is there something mroe major going on?
This is seriously starting to hurt my wallets, so if someone could halp me quick!!




where would this fuel pressure regulator be? i've never heard of this.

could be a stuck close fuel pressure regulator, maybe the eavc, a vaccuum leak could also case it and your timing being off would add aid in creating this problem.

the fuel pressure regulator is on the fuel rail of the intake manifold and the eavc is behind the intake manifold. you can try and clean it out with carb cleaner before replacing the eavc (dont spay in the coolant lines, unbolt the eavc and you'll see what i mean). dont get worried f your car doesnt start right away after you spray the eavc, that stuff has to dry off (or burn off) first.