ok well on wednesday some lady backed up into the front left part of my civic, so i collected all of her info and went on with the day after i left the scene and i was at a red light i put my car into neutral and released the clutch and the gas and jsut had my foot on the break but my rpms would just rev up to 2,000 rpm and then go back down to 1,000 and it would keep repeating it so i checked it out and it looked like there was nothing wrong with it so i brought it to a mechanic to do diagnostics on it to see what was wrong and he said that it was my msd that was causing it cause it got damaged a little plus he said i had to many after market parts for him to find the source so i said ok and later that night i removed the msd igniton and it still continued to do it. can u possibly help me think of what it might be and how i can fix this problem thank you very much

 

well what parts do you have? are you somehow altering your air fuel ratio? aftermarket ecu? upgraded fuel system? it could be so many things yet again, you basically have to go back and recheck or reinstall all your mods that are before your exhaust manifold.

 

It seems like to me it's your Fast Idle Thermo Valve. Which is under the Throttle Body. If you take it off
open it and check to see if the Vavle is screwed in.

 

CTR 94 is right.....i had the same problem. My idle would oscillate up and down between 1k and 2k rpm. I don't know what caused it. Though what i did was to went ahead and replace my intake manifold and the problem went away.