1993 Honda Civic

Hello I own a 1993 honda civic ex it has the original motor(150,000miles) but has a idling problem as soon as the engine starts it goes all the way up to 3000 rpm an stays there for about 10 seconds then it surges between 1500 rpm an 2500rpm an doesnt stop. When I turn the air conditioner on it will sometimes idle normal. When the car is cruising it will slowly accelerate with my foot off of the gas pedal I have tried a tune up an still no luck im thinking it is the idle sensor or oxygen sensor but im not sure.

all information will be greatly appreciated Ryan
May 11, 2006.

Are you getting a check engine light? It surges whether the engine is hot or cold. Have you had any work done to the intake manifold area? Another concern is the coolant level of the engine. If it is low or has air pockets this can cause the problem as well. Try bleeding the system. The idle air control valve can mess with this as well. The IAC senses the temp of the coolant and helps the engine regulate the fuel needed, much like the old carb and choke system. When it is out of whack the engine is confused on the mixture of fuel to supply. Another good possibility is the idle air sensor that is located opposite the throttle cam on the throttle body. Sometimes as they get older they stick and this is a cause as well.

Bruce Hunt
May 11, 2006.
No he doesn't have a check engine light and it does surge no matter what the weather is. The only thing he has on there is a cheapy short ram intake from advance, but he had that on a while before this started. We bled the coolant and it is good. We still have to check the other sensors though. Maybe get lucky.

May 11, 2006.