Hi, recently picked up an 84 Stang and need some help! It has a 302/C4 auto. Did not run when I bought it. I removed the CFI setup, and replaced it w/ a rebuilt 2bbl carb. Removed the frame mounted hi pressure pump, and wired the lo pressure in tank pump to run when the motor is on. Holds a steady 5psi. Also converted from TFI to the Duraspark ignition, with the vacuum advance distributor, though I am still using the TFI coil. Now here's my problem...Engine fires up fine and stays running. Idle is very high(1200 rpm), even though I have the idle adj. set as low as it will go. When I open the throttle, engine shudders as it revs up. When it is put in gear idle drops to about 450 rpm. No power, can barely make it up the driveway! Test drives so far have not been very exciting. I have tried everything I can think of with no luck. I have plugged almost every vacuum port. Currently the only vacuum pulls hooked up to the motor are the vac. advance and tranny's modulator valve, but the EGR unit is still bolted to the manifold, still looking for a blockoff plate for it. PLEASE help! Engine doesn't smoke or knock. Good oil & fuel pressure. Timing is set at 10*btdc.
No reason to have an EGR b-off plate. I just took the spacer out. I found that with my setup that I got a better torque curve without it, even though I lost a few peak HP.
Sounds as if you are having ignition trouble. I'm not that good at it. The shudder also tells me that you may have either wires crossed, or not in firing order. I believe those engines went with the 302 firing order, not the 351 order like the 5.0 HO carb engines of that year.
I also wonder about firing with the TFI coil. While it may be okay, I am not positive it would be. Coils are pretty cheap.
5PSI is a hair low. Holleys like 6-6.5PSI. This shouldn't be your issue since you are worried about keeping the bowl full, not having pressure to spray from an injector.
Try this site and look at the EFI-CARB wiring to see if it helps at all.