My car starts fine but when it warms up it idles low "300 - 400 rpms". When i have my AC on it drops even lower and almost wants to stall but doesn't and it will keep doing that over and aver again. I have had a diagnostics computer hooked up to it and i get no codes.. My car is a 99 civic EX stock with 94,000 miles. Should i manually adjust the idle or could it be my O2 sensors or my Idle control valve.. If i manually adjust the timing and I have a bad ICV what would the result be and the same for the O2 sensors.. All plugs, wires, Dis cap, and rotor have been changed 2000 miles ago. The car runs fine other than at idle. And I also notice that if it sits at an idle too long it will overheat after time (15 mins or so) but comes down as soon as i give it a little gas.. Could that be a result from an idle that is too low or could it be my water pump?? I'm stumped and could use some help

Mtch (PeckerWood)

 

Manually adjust the idle a bit. If you aren't experiencing any other weirdness (large idle fluctuations, lopey idle) that's probably all it is.


Take care of that first and then worry about the overheating. It could be a result of a low idle... water pump isn't spinning quite as fast as it normally would be.