Surging idel

My cars rpms surge no matter how warm the engin gets. The only time it stops surging is when i get the rpms past 4000. even when i drive under 4000 the car will drive funny, the speed will go from fast to slow fast slow and so on. And I am not sure what could be causing this. could it be the TPS (throttle position sensor) or just the throttel body. or maby a injector is stuck open. i also think i might have a bad o2 sensor (because yes, the check engin light is on). is it ok to drive it as long as i run it on higher rpms? some one please help. Thanks

on the bottom of your throttle bogy there i a valve assembly. it is called a fast spsed idle valve this is most likely you problem. it is very common to go on hondas.just get one from your local honda dealer they will most likely have it in stock and dont forget the throttle body gasket.

what exacy does that do and how hard is it to replace

I put an article out about this on this forum. Now, you have a check engine light on and problems. Find the code on the ECU. Then you will have something to work with. Don't go jumping around until you know the code. Finding it is free. I am not going to explain how to do it. There are plenty of sights around that explain the shorting of the ecu clip and counting the light flashes to reveal the code(s). I have found that there are many reasons for the surging. Have you have anything done to the engine recently or so? I found that problem was related to the intake manifold and a leak of air into the mainifold at the gasket. The extra air causes the ecu to try and compensate with fuel for the air. The result is the engine surging. There are other reasons why the engine surges. Get the code. I bought a OBD2 scanner on ebay for $35. Great investment on my part. It reads any car 1996 or newer. Let me know what you find out.