My civic is not running happy. The RPM fluctuates on my car all day and some time even turns off! I have this really weird clicking noise when I start it and it last for about 15mins from start to running time, then it goes away, until the next time I shut it down and start it again. It doesn't matter it I shut it off for 5 minute or over night, I get the same sound. You can here the sound only on acceleration and deceleration and like I said, its for the 1st approx. 15 mins. I changed so many things in my car and I am going crazy with it. I haven't lost any compression and I can still drive it over 100mph. She'll do it with no prob. its just when I get back to a stop, it shuts off while waiting at a light. while driving and I step on the gas, everything feels good, Its when I take my foot off the gas, its sometimes real ruff. I have changed the timing belt, all drive belts valve cover gasket, water pump, cam seal, shaft seal, brakes/flush, oil ( syntec) and filter,pcv valve, cleaned throttle control valve and a few more things I can't think of right this minute and its still not running right? any one know something I miss or can try? check eng light hasn't come one since I changed the O2 sensor... HELP???

Vandy-1

Could be the EGR Valve going bad.