i have a 94 z28 camaro, with a freshly built automatic 4l60e transmission 5000 miles ago. i know its not the transmission cause it has fits where sometimes everything is fine and other times it pisses me off. when its acting up it doesnt take off in first and there is no over drive. i took it to aamco transmission and they hook it up to a scanner they said its a wiring problem or ecu. so basically i need to run down every thing i need to know where to and how to check

 

this is for 99, it might help

 

Are you setting codes and is so what are they, What stall converter do you have?