Mechanics

VORTEC 5700 V8 SFI ENGINE PROBLEMS

2002 GMC Savana

Engine problem
2002 GMC Savana V8 Two Wheel Drive Automatic 76000 miles

I bought this truck new and started having issues in the first year. The dealer claimed they could not replicate the problem. The service engine light would come on when I was speeding up to get on a highway or going up a steep hill. The light would come on as it slipped into the last gear and the truck would shutter and loose power and act like it was going to stall. No back firing just loss of power. I brought it to a non dealership mechanic after it was out of warranty and he pulled multiple trouble codes for mis fires on random cylinders. These were the only codes recorded so I guess the dealership forgot to tell me this. My Mechanic did a complete tune up and then replaced the fuel injection system(spider) with a new one(new style). It seamed to solve the problem for a while but now it is even worse than before. What could the problem be?
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Ckshannon
December 16, 2007.




I take it the fuel pressure is good. Has it given any more codes since then? Those CPI engines had issues with crank angle sensors. Did your mechanic find any codes related to anything else?

Tiny
Jack42
Dec 17, 2007.
I am not sure they tested the pressure. They said that because it fails under load it is hard to measure the flow under those conditions. It runs fine until it is going into its last gear going on a highway or going up a hill, it is a sure thing it will fail with the AC on going up a hill.
Would failure of the crank angle sensors cause the behavior I am describing. They indicated that the only code was for multiple and random cylinder misfires. Thanks for your help with this.
Chris
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Tiny
Ckshannon
Dec 17, 2007.
Iti spossible the crank sensor could do that, I hate to just throw parts at it. Have they checked the fuel pressure with a gauge while driving it? Any other codes shown up?

Tiny
Jack42
Dec 18, 2007.
A fellow wrote he had the same issue and directed me to service bulletin #1539013. I brought it to another dealer and they discovered the valve guides were damaged and the heads need to be sent out and machined. When I asked the mechanic if sticking valves could of cause this he said it could and over time it did damage. Odd the selling dealership was not aware of the valve problems while it was under warranty and having issues.
Ckshannon

Tiny
Ckshannon
Aug 11, 2008.

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