This may or may not be the place for this but here it goes. 94 Chevy 4x4 ex cab pickup. 350 tbi. No codes. tps is fine, o2 is fine, egr is fine, fuel pressure is 13 psi. New distributor and module, new plugs and wires, new fuel pump, timing is 4* btdc at base. I have a stumble at throttle tip in and rough idle. The truck drives out of it when you open the throttle. Only happens at low rpm and or small throttle opening. ?????????????

 

Fuel pressure stays steady at tip in? I would start and check that the IAS value is 4-8 steps at idle and op temp. If not, you adjust the idle set screw on the tbi with car off a slight turn, start car and check again at op temp. That is the only thing off the top of my head other than checking your base timing that would affect this if you have not altered the tune.

 

Fuel pressure stays rock solid. I did bump the distributor back a little(retarded) and it seemed to help. I also unplugged the o2 just to get the computer to try and set a code and it did but only after a half hour of driving. Seems odd to me.