Fresh resto with engine problems? Wont stay running

[circuitguy]

Got a new problem now.. Once the exhaust was installed the truck ran sluggish and would stumble off idle. Now today it wont even start up. I can get it to start if I hold the gas pedal down, seems to run good while I am doing that. Once I release it it will drop to about 400 rpm then die. No check engine light and I know its not a fuel problem. I unplugged the TPS and nothing changed, any ideas?? I need help bad!

87 GMC R10 5.7 TBI

 

[Georgeb]

first place I would check is the IAC valve. Try resetting it to zero. Can you read data like with a laptop or something? It would be nice to know if it moves and how far open it is at startup.

 

[Georgeb]

Also someone on here has a great troubleshooting guide for TBI perhaps they will post it. The best tool I have is my ability to connect via my laptop.

 

[Georgeb]

Found it!
http://www.gmsquarebody.com/forum/showthread.php?t=8719