350 vortec swap
New crate motor from Gm,ecm,chip from hypertech,distributor,coil,plugs,wires,fuel pump,trans, idle air control,tps, oil pressure switches, coolant sensor,knock sensor.

Will fire right up and run but idle goes up and down like it wants to cut off. Once warm it does it a little slower. Has anyone had this problem?

 

Probably just needs a tune, this treat could lead you in the right direction https://www.thirdgen.org/forums/diy-...-5700-rpm.html

My engine still does it wery little for around 1 minute after a start up in cooler themperatures.