Fuel issue

[Tankeryanker]

Hey guys, I have a 2002 tahoe 5.3 flex fuel with supposedly normal fuel pressure, about 50 psi with the key only turned on, engine not running and drops to 42 and will go up to 52 depending on amount of throttle. It will drop to 20 upon very hard acceleration. When it is run for a while the fuel pressure will drop to 0, especially when it is hot. The car will shut off and I have to pull over and let it set for 5 minutes before it will build pressure to start. A new fuel pump (factory ac delco)was put in a year and a half ago. Could it be vapor locking? any ideas? What is the little box that the fuel filter outlet line goes into then up to the motor?

 

[gpracer1]

This is the 91-99 section, you might have better luck or more info from the 2000-2006 section.

 

[retorq]

That does sound like vapor lock, it happened to me a few weekends ago, was on the highway, came around the corner and nothing ... no fuel pressure, I pulled the cap off and there was a HUGE vacuum release ... I replaced my cap with a new vented cap from the parts store and it's been fine. No more vacuum build up so far ... mine is also a new pump.