Rep Power: 0

After idling for 10-20 minutes or so my 03 civic ex mt will begin to drop the rpm down to 400-500 rpm's and just as I think it is going to stall it rev's it up to about 1500-2000 rpm's. What is going on? I'm new to Honda and fuel injection so any help would be much appreciated

 
Rep Power: 812

clean out the idle air control valve on the throttle body. sounds like its stuck with carbon buildup.

https://www.civicforums.com/forums/7...e-up-mods.html

 
Rep Power: 0

Remove the throttle body and Idle control valve and clean both.

 
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I also have pretty much the same problem (if it even is a problem) i think? When I first start the car up in the morning it sits idled at about 1500 rpms (which I think is high?) Then over time, the rpms continue to drop gradually to about 600-700. Is this supposed to happen or do I need to do some cleaning also?

 
Rep Power: 812

thats normal, when its cold the rpms stay high to warm the engine up faster. then it should gradually drop down to 700rpms as coolant temp increases. on warm days usually you wont notice or rpm wont be very high.

 
Rep Power: 0

Ok thanks, I thought it was normal, but figured I better run it by the almighty gearbox to be sure. lol!

 
Rep Power: 0

hey guys im new here, i have an 04 civic auto woth 130,000 miles, last week i turned the car on and all of the sudden as soon as it started it stalled, i started again and it stalled again, then i tried starting it and it would turn over but not start, finaly i pushed the gas petal and tried starting it and finally it got started, i did not have this problem again yet however i am worried, because from then on the car has been idleing at abour 400-500 rpm, i when and got fuel injector cleaner and put in 93 gas figuring perhaps i had bad gas, two fill ups later still idleing real low, im not sure what to do, anyone have suggestions, sounds smular to the problem abouve however alittle different situation so hoping i can get some advice, thanks