5.7l vortec hesitating?

Flagster

Expedition Leader
Need some advice where to start...
Recently on cold starts and at low RPM when warm the motor in my 2000 GMC 3500 is hesitating...?
Stutters until I can get the RPMs up?
Any advice on what to chase?
Thanks
Matt
 

bob91yj

Resident **************
Not much to go on there, what's the mileage, last time plugs were changed, any recent work performed on the engine, etc?
 

shortbus4x4

Expedition Leader
Check your cap and rotor, I have seen many Vortecs with corroded ones that have problems. Also check fuel pump pressure. Vortecs are pretty picky on pressure, just 5 psi too little can cause no/hard starts, etc.
 

berg

Observer
Fuel regulator would be on my list to check

To check for a ruptured regulator diaphram, remove the vacuum hose from the regulator and look for fuel coming out of the vac port of the regulator when the pump runs.

easy and quick to check.
 

kawamatt2

New member
Fuel regulator would be on my list to check

To check for a ruptured regulator diaphram, remove the vacuum hose from the regulator and look for fuel coming out of the vac port of the regulator when the pump runs.

easy and quick to check.

Never worked on the vortec engine have ya? The fuel pressure regulator is inside the intake manifold. Hence it needs no vacuum line. You have to remove the the upper plastic intake cover to access.

In any event, to the OP, I would do a general TuneUp first. Plugs, cap, rotor,fuel filter, and make sure all your plug wires are in good shape. Take note of how the plugs looks when removing them to possibly pinpoint a problem cylinder. If that doesn't fix your problem then you should check fuel pressure. Possibly you've got a week fuel pump as mentioned.

For all you ever might want to know about the vortec engine, go here. http://pacificp.com/forum/
 

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