Hello. I have a 1999 GMC Sierra Classic with 5.7 Vortec and 269,000 miles. Had the Fuel pump, fuel tank and fuel filter replaced. Ever since, it starts hard after sitting over night or for long periods of time. Maybe cranks for 5-7 seconds or so to start. After that, it fires right up like it did before the old pump stopped working. I took it back to the shop, they said everything looked fine, and could not get it to duplicate the hard start condition,,,Even after it was parked overnight (??). They suggested I replace plugs, wires, cap and rotor--I replaced plugs but all items were replaced 30k ago. I put a fuel gauge on and had the following readings: With key in "on" position=about 64psi. When started=about 54psi while running,,Hitting the gas, it would jump up to about 62psi or so, and down to about 50psi momentarily when off the pedal...then settle back to the 54psi. Shutting off the engine, pressure dropped maybe 4 or 5psi and held steady for at least 45 minutes....after that i disconnected the gauge. Any thoughts on what might be causing the long start condition??
