Just finished my complete engine rebuild and started it yesterday. It ran like a beast (not driven) but it won't idle. I ran it for 20 minutes at 2000 RPM to break in the cam and as soon as I get off the throttle it will stall.

I have a 350 stock crank and rods, with KB pistons and LT 4 heads and intake. I am running a CC-306 cam and had the ECM programmed by PCMFORLESS.com

I have been reading that possible problems might be the rockers are too tight, I have CC pro magnum full rolloer and lashed them to the point where you couldn't spin the pushrod method. I heard that isn't right, is that true??

I also heard that it could be my IAC, what is the way of checking it and cleaning it??

Any other Ideas for fixing the problem???

Thanks
John

 

I had the same problem at first with my rebuild. What I did was adjust the throttle blades using the set screw so the throttle body lets more air in.

 

What he said and also, when I put in my CC305, it took my car almost 45 minutes of rough idling before my computer kinda caught on to what was going on and "relearned" the idle. Sounds like you lashed the valves alright. If the rockers were too tight and you were revving the car to 2k, you would have a bunch of bent pushrods like I did. I would say for the most part, your computer just hasnt relearned everything which is causing it to no run correctly.