I recently put my car on the road and im having a couple minor problems.

1.) When I start it up, it will bob up and down in idle from 1000-1500 RPM. This only happens in park and neutral sometimes. When in drive it holds a good steady idle but its at 1000 RPM. It threw a IAC code and I replaced it and it still does it!

2.) My cooling fan stays comes on after running for about 1 min, and stays on. I reset the computer like anothe thread said to do but it is still doing it. The relay is fine also, I ckecked that.

3.) My cooling temp. heats up to 260 then cools far below 190! A big flucuation!

ANY HELP WOULD BE GREAT, I NEED TO FIX THIS SO I CAN GET IT TUNED IN MAY!

1) Vacuum leak- possibly blown out intake manifold o-ring or throttle body o-ring, or a crack in the manifold, or a loose/disconnected/split vacuum line.

2) see # 3 first.

3) Sticky thermostat. Could also possibly be a bad coolant temp sensor or something wrong with the wiring thereof (chaffed, intermittently grounding/shorting to power). Fix these before moving on to 2 as these are probably the CAUSE of #2.




Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said

I thought about a vacuum leak but my gauge say around 19 hg, although I should be at 20 hg it is idling at 1000 rpm which should be about 19 hg! I dont know!!!!!

wiring problem with the IAC??
When my car would go between 1000 and 1500, it was the gasket between the intake manifold and the plenum. I replaced that, and it was all good. Double check all the other things past the throttle plate.