[Old Dave]

You need a minimum of 55-61 lbs. of fuel pressure at the test port on the fuel rail 2 sec. after you turn the key to "ON" ...NOT START. The pump should come on and run for 2 sec. and then shut down after it pumps up to pressure. These Vortec's are very picky about the minimum fuel pressure and sometimes won't start if it's even 1 Lb. too low. I fought my 97 Suburban for about 6 mo. with long starts (5-8 min.) and my pressure was 54 Lbs. key on not running. Replaced the pump about 18 mo. ago and it's been fine since. You might try replacing the in-line fuel filter first since it's much easier and cheaper than the pump. It's located along the frame rail just behind the driver's seat. I would only use the WIX brand and they have an arrow on them indicating which way they go on. FYI, mine had 118K on the OEM pump. Good luck.