I seem to have bleed down somewhere in my fuel system on my 97 Z28. When I go to start the car after it has sat for probably a half hour or more the first time I crank the engine it doesn't want to start, I might crank it for no more than 3-5 sec's. I then stop and try it again and it pops right off. I have recently replaced both the regulator (new Napa piece) and a new fuel pump(Racetronix) because the factory one was weak only putting out 35psi under WOT. At idle the with the new pump the fuel pressure read 38psi, I removed the vac hose from the regulator and it his 46psi.

What could it be? Could I have a bad regulator? or could I have done something wrong when I installed the pump. This problem existed before both the new regulator and pump were installed.

Thanks.

 

Assuming the new pump has a check valve built into it and you already replaced the FPR then the only other thing it could be is an injector. Lift up the fuel rails and pressurize the system with fuel pump prime connector and see which one(s) are leaking.