here goes, another weird idle question...current setup:gsr motor in eg, stock p72 ecu. i start my motor when its cold, 3000 rpm idle...then drops suddenly to 2k then climbs back to 3k and does this over and over. the car drives fine though. when motor is warmed up, it goes from 2k rpm, then suddenly drops to 1k. turn on the AC, and it stabalizes (sometimes) at 1500 rpm, which is still a little high for a warm idle... took a look under the hood, antifreeze around the top of my radiator, and nothing in the overflow plastic thing. tonight i checked the level in my radiator and fluid level was to the top, but still, nothing in my overflow. filled the overflow thing. and car did the same thing with the weird idle. so im thinking i have a leak in my radiator, or from the hose or whatever. car never over heated or anything. but would a low coolant level or air in the coolant system cause this weird *** idle? i dont think its my tps, cuz 1. its not throwing a code, and 2. it hasnt been messed with, unless magically, things get changed when im not looking. any help besides people telling me to search would help, already searched last night for a good hour. thanks in advance

 

Might try to clean your iacv?

Worked for my buddies LS when a jumping idle at operating temperature.

 

air in your coolant could cause an erratic idle,..also cleaning the screen on your IACV might help

 

ok, so it sounds like its air in my coolant, because it looked like it had just happened recently (within the week). and could someone tell me where exactly i could find this thing called IACV? intake air cylinder valve? am i close? lol

 

IACV = Idle Air Control Valve

and its located on the back of the intake manifold,..close to the firewall

 

cool, thanks for that info