I rebuilt a 3.8 V-6 in a 1999 camaro due to a spun rod bearing.

After getting it all back together, it wont hold an idle, it just starts up then dies right off, even after throttling it up and trying to go back to idle it dies!

But I did find out that if you pull the brake booster vacuum line, it will stay running, but obviously sparatic idle due to an unmetered intake of air.

To me it seems like an idle air sensor, or the throttle position sensor.
If anyone has an idea of suggestion, id be more than happy!

 

unplug the maf sensor and see if it gets better. also make sure everything is plugged in

 

check all the sensors, map, maf, iat, reset your tps.

 

Any Codes ?

 

Having comp. scanned tomorrow, dont know about engine codes yet. However I did have the exhaust cut about three inches from the o2 sensor after the cat. After I welded exhaust back up, car runs allright, but still a little hesitant on startups.