losing fuel pressure
 

Well the title says it i am losing fuel pressure. i will be driving on the freeway for an hour to a hour and half then my fuel pressure will start dropping. It will start to get down into about 30psi and if you dont keep the revs up it will start dropping until the car will eventually lose all pressure. i will wait a 1/2 hour then it will run for a little bit maybe 20 to 25 minutes. i just installed a new holley 255lph fuel pump and new fuel filter before this started happening. i checked the volts on the battery the alternator and the fuel pump it all seems to be good. i am really confused. my car is going to the transmission shop right now to fix a problem, it isnt shifting till 6000rpms in every gear, but that is a different issue. any ideas??? maybe fuel relay??

Re: losing fuel pressure
 

Sounds like vapor lock. Since it started when you replaced the pump, there may be air getting in on one of the connections. It is a PITA to trace down.

Re: losing fuel pressure
 

I don't see how that's possible unless there is a leak in the tank before the pump making it suck air. Otherwise everything is pressurized and would leak fuel. I would suspect the new pump or the regulator. You could squeeze the return line when the pressure starts to drop. If it comes back up, it's the regulator. Did you replace the short suction line in the tank and with the right hose?