[JJAB]

Updating, for all you guys that scratched your heads along with me on this "ISSUE". The owner of the truck took it to a local tuner. Of course he began by checking all normal things, sensors, 02 readings, the tune itself ,etc... Getting to the point, he says that it is definately a fuel issue and not a tuning issue. He says the the pressure starts out at 60 psi on initial start and maintains at 55 - 58 for a certain time period. For some reason, the fuel pressure then drops or falls to 20psi, like the fuel system is getting air in the line. At this point he says he is serching for the reason it is doing so.

I installed the new tank and sending unit and I can remember that the sending had three ports. Fuel feed to the intake, fuel return, from the intake and a vent port. The vent port, I just left open. Originally, I ran it to the vacuum canister but later just left it unblocked. Could that be the problem.

Oh, I am running a 1987 blazer tank with the in the tank fuel pump, Airtex 3270(A/C Delco EP381 equivalent). One last thing, I also did not change fuel injetors, they are the stock truck injectors. I had them checked and they were verified to not be stopped up. What you think.