Honda Car Forum

Both of my cars seem to be doin the same thing. When in park the RPMS will jump it goes up and down up and down... when in drive its fine. It just seems to idle strange when its in park, its so freaking annoying.. im thinking a sensor of some kind, but maybe not.... the thing throwing me off is both of my cars are doin the exact same thing so im hoping its something commonly known....

93 Honda del sol and 99 Honda crv shifter do go in park when stop. Honda not annoying, do last forever. Its maybe computer. When drive, they do go ok since Honda. Motor ok, its Honda, and Honda do rock!!!!! Engine sensor no problem. Both cars doing same thing. They Honda, so do same thing. Must check idling computer.

The typical cause of what you describe is a build-up of carbon in the idle air control valve. That valve has passages inside that allow air to flow around the throttle plates when the car is at a stop so that the engine can continue to run and not stall. The idle air control valve is a small electric motor that has a plunger that extends into the air passage to allow air or block some of the air that is bypassing the throttle plates. By constantly adjusting the amount of air bypassing the throttle plates based on engine operating conditions such as load and temperature the valve maintains a smooth engine idle.if the plunger of idle air valve is sticking the result will be an idle that goes up and down as the valve doesn't smoothly regulate the air bypass port. the plunger sticks because of a carbon build up (think of soot in a chimney) that restricts the movement of the plunger.a second cause is that the air bypass passage inside the valve is plugged with carbon build-up. when that happens no air can flow through the valve and the result is that the engine starts 'gulping' for air at idle by pulling the throttle plates open and the spring pressure snapping them shut.That's the only thing in common between the two cars that would cause the two different cars to have the same symptoms. To fix it you have to clean the throttle body and clean or replace the idle air control valve. You can clean the throttle body and plates with a commercially available spray cleaner such as a carburetor cleaner or throttle body cleaner that you can buy in a parts store. the idle air control valve has to be taken off the throttle body to clean it and its better left to someone who knows what they're doing rather than trying to do it yourself. the succsss rate for cleaning the idle air control valve is about 40%; usually if they're plugged you have to replace them.hope that helps