PMC 5.7 wont run past idle

[Reming870]

2009 PMC 5.7 L with "PMC Fuel Control Center" (FCC) with low and high pressure pumps with a return system.

Motor M# 50-570-06, Ser# 690034

I have changed all fuel filter/seperators (including the internal one in the FCC), plugs, wires, Distributer cap.

Problem occurring after de-winterizing this weekend. It will only idle and the idle is rough. If I ease gas into the throttle body with a Dixie cup it will smooth out. I have also tried an external tank with no difference. Opening the throttle causes it to stall. If I jerk the throttle fast I can get the RPMs up but the engine is backfiring.

I have not checked fuel pressure, but the problem is bothering so I decided to post. Still unsure at this point if it is an electrical or fuel issue.

 

[Reming870]

Low pressure fuel was the problem. I removed both operating pumps and cleaned in alcohol. 38 PSI steady now, was 25 PSI.
Now I have a surging problem. RPMs are floating about 1000 and I cannot maintain a consistent RPM.

 

[Walt T]

You still have a feed problem. If not the pumps then it's the throttle body. Try testing the TPS on the side of the throttle body. Has 3 wires, disconnect and use an ohmmeter over two of the three while moving the throttle. You should have a good staedy movement of the ohmmeter reading. This actually works best with an analog meter with a needle.If it's all smooth operation then you may be looking at clogged injectors. Maybe run some BG44K through the system