Where to start? It's a 94 k1500 with an 86 5.7, 85 heads, slotted center bolt holes on 94 intake (no leaks), swapped to hei distributor, still using tbi but about to go with edlebrock performer intake and 750 edelbrock carb I think. I originally changed all sensors, went through wiring testing and fixing every problem I could find because of rough idle and stalling. New fuel pump sock and filter, rebuilt pressure regulator, the more I do the worse it runs. Wouldn't run with egr plugged in and timing wire plugged in. (Egr circuit tested bad and was opening at idle) Ran great for about a month then would idle all day until I took off then would only go about a block before no start no fire. Changed to hei now runs and drives but stumbles on hard acceleration. I noticed at half throttle both injectors spray then skip sorta like there's air in the line or something. Wasn't doing that before hei. I think I've been fighting a failing pcm this whole time but who knows. Has always had a miss at idle even before I changed motors and all the parts. At this point I'm ready to change the trans to non electric shift and throw half the wiring away with he pcm. Any input about swapping to hei and carb or easiest route to do away with the pcm on the transmission aspect would be appreciated. Trans is 4l60e and only about 5000 miles on rebuild with "beefier than oem" parts and stage 2 kit, so if I could keep using it would be a plus but not a must. Thanks for reading and for any comments.

 

It’s probably just the way you typed it, but did you mean “new fuel pump sock” or new fuel pump and sock? Either way I’d recommend a current draw test. The pump may be new but high resistance in the pump wiring will affect the pump’s ability to deliver adequate pressure and volume.

The pump draw test is easily done at the fuel pump relay. Anything more than about 10 amps is cause to suspect the wiring (or a faulty new pump).

For the injector spray pattern to skip like you describe (as well as hesitation/sagging) indicates a fuel supply problem; however the possibility that the ECM is detecting conditions that are causing it to decrease the pulse width and lean out the A-F mix can’t be overlooked.

Have you checked for diagnostic codes?

 

Been a while since the last fuel pressure test but it was good. Haven't done a current draw test just continuity and parasitic draw along with testing egr circuit and solenoid, tps and circuit, iac and circuit, coil and pickup. I'm not the best at tracking down electrical issues but I read up and go test, read some more, go test. Also fuel pump is not new. Injector skip only appeared after hei swap though. Connected power to keyed power, tach wire to the pcm signal wire and guage wire but wondering if I missed something there. Ive found conflicting info on that as far as if the pcm needs tach signal or not. When all sensors and original wiring was connected there were no dtc's. I'll get back to you on the pump circuit current draw test.... and pressure test again as well.

 

Injector pulse and spark are both based off the cam sensor in the distributor.

Did you adapt the original distributor for HEI, order a new distributor or install a used? If it’s a replacement distributor, what year is it for?