Ok, I have a boosted zc with an oversized throttle body and stock ecu. when I start the car cold I have to crank it then stop about three times before it fires up. Then it runs for a few seconds with an extremely low idle and dies. Then I start it again and it idles around 600rpm for a while and then creeps up to about 1000rpm. after taking off and stopping a few times the idle surges from about 500 to 2000. If I unplug the iacv the surging goes away. I have replaced the iacv three times with the same result. It surges sometimes, but not all the time.
So what I am wondering is what the hell causes this, and shouldn't I have a high idle until the car warms up? Also, i have noticed when the car surges my o2 voltage goes to zero, the idle drops, o2 voltage is normal, car surges o2 voltage goes to zero, idle drops, and so on. Is the computer cutting fuel to get the idle down or what? I have replaced the o2 sensor several times too.

 

bump for help

 

based upon the other thread you made im leaning towards a wiring issue...an 02 sensor and iacv are not parts that need to be changed frequently...

 

I am kinda thinking low voltage or bad ecu ground, does this make sense?

 

bump