Strange Starting Problem

[InfamousGadget]

99 GMC Sierra Truck, 4.8L V8

When the car is stone cold (overnight, 8+ hours in MI Winter Weather) the engine will start fine.

When the car has sat out for only a few hours (1-2 hrs) the engine has a harder time starting. It's cranking, but it'll take 3 or 4 tries and pumping the gas to get it going.
Once it gets going it'll stay going fine and run without problems.

If it's only been off for a little while (less than 1 hr) it'll start up first try.


Anyone have any clue as to why the car is having trouble getting going when it's been sitting for an hour or so?

[2000CAYukon]

Sounds like a fuel pressure regulator or a stick injector. Fuel leaks into the engine, flooding it which makes it hard to start.

A fuel gauge will tell you if that is your problem. The fuel pressure should not drop much after you shut off the engine.

//2000CAYukon

[truk993]

My 99 5.3L had same problem. Easy inexpensive fix was the fuel pressure regulator. I'd check that first.