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5.7l cold start hesitation and stalling

kragar

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kragar New Member

kragar

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I have a 99 GMC full size truck which is the old style still and has 5.7 engine. The truck starts fine but has a bad hesitation when cold at idle, it will "miss a beat". It will stall periodically too. If I take out when cold it wil spit and sputter when accelerating normal. If I floor it then it will accelerate fine. Truck runs fine when warmed up. It acts like bad plug wires but they are new as well as plugs, new fuel filter as well. Also put on a throtle position sensor on too.

No light coming on on dash.

Any help????

 

Craig

jnperin Enthusiast

jnperin

Posted
Posted

Had the same problem with my 98. All I did was run some injector cleaner through it and it is noticely better but still not 100%. Some one told me that it could also be the injectors or a vaccum leak.

 

Jim

kragar New Member

kragar

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Big Wheelin, where exactly is the fuel pressure regulator. I will look at it tonight to see if it has a leak.

Also, truck seems fine when it is warmed up as well.

Steve Ks Enthusiast

Steve Ks

Posted
Posted
I have a 99 GMC full size truck which is the old style still and has 5.7 engine. The truck starts fine but has a bad hesitation when cold at idle, it will "miss a beat". It will stall periodically too. If I take out when cold it wil spit and sputter when accelerating normal. If I floor it then it will accelerate fine. Truck runs fine when warmed up. It acts like bad plug wires but they are new as well as plugs, new fuel filter as well. Also put on a throtle position sensor on too.

No light coming on on dash.

Any help????

 

Craig

 

 

 

 

Had the same problem with my 99. However mine is the 5.3L and newer body style. It turned out to be the fuel pressure regulator ($50). After it is warm, shut it off and pull the vacuum hose off the fuel pressure regulator and see if gas runs out of the vacuum hose. If gas comes out it is a bad regulator. The one on my 99 is on the drivers side on top of the valve cover about mid way from front to back. The only vacuum line coming out that side goes to the fuel regulator. I don't know if the 5.7 is set up the same. Good luck.

kc5deb Enthusiast

kc5deb

Posted
Posted

I'm having the same problem in my '02 6.0L. If it's a little cold outside, it'll hit on a few cylinders, but, run for a second like it's running out of gas. I've checked the pressure regulator, and think that's fine. I'll check it again this afternoon.

 

Would anything else cause pressure to be released from the fuel line (check valve, fuel pump, etc), causing the fuel to run back down into the tank, therefor causing the hesitating starting?

  • 4 weeks later...
  • 3 months later...
00Tahoe Enthusiast

00Tahoe

Posted
Posted

I had the same problem, turned out to be the intake manifold gasket. It would rev between 300-1100 rpm's while idling. I could gun the engine and try to get it warm quickly and then all would be okay until the next morning.

00Tahoe Enthusiast

00Tahoe

Posted
Posted

I had the same problem, turned out to be the intake manifold gasket. It would rev between 300-1100 rpm's while idling. I could gun the engine and try to get it warm quickly and then all would be okay until the next morning.

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