Agreed, but why. Injectors leaking down? No gas smell out of the exhaust upon startup. regulator leaking down, pump output weak or lack of supply. Need to install clear fuel tube to check for air on low pressure side.

Actually I think its your high pressure pump, it cannot keep up. The pump should be able to reach 60 psi and a bit more during test. The pump can be tested but if tested need to make sure the pressure does not exceed 60 psi because it can damage the regulator.

Edit: could also be the regulator

Is the high pressure pump on this the same as cool fuel ?? I know VST has the lift pump and CFuel doesnt

Is there a regulator on top of the vst? Or just the one near the test port on the rail? What is under the Allen bolt atop the vst just between the two pump leads?

Once again, thanks for the replies and help guys. Much appreciated.

This is not the cool fuel setup. This has an old school lift pump driven by the accessories feeding the vst which houses the high pressure fuel pump. Stupid vst is a giant carb bowl with an electric fuel pump in it instead of jets.

Throw that chit in the trash...LOL.......put an Aeromotive A1000, bypass regulator, return to the tank and be done with it...

I made this up to tell another how to switch from VST to cool fuel, but should help. The regulator is on the fuel rail up front under the plenum. Any over pressure is return to the VST by the regulator

Have to agree with you, my VST was working just fine, but when I repowered I changed over to cool fuel and have a steady 40 psi and return to the tank. That said, to return to the tank the rail needs to be modified to accept AN fittings

I'm 100% cool with ditching the entire system as long as i can get the rail to play with a different pump and reg. Sending return back to the tank is cake.

Not that ditching the system wouldn't be a good move, but it may be a simple issue which needs fixed. Suggest doing your low pressure test before going the route. Removed my VST and it was working fine, just wanted to go MEFI 3, cool fuel and return to tank when doing repower.