97 Suburban sluggish (and sometimes "backfiring")

Tiny
MMACARTHUR
  • MEMBER
  • 1997 CHEVROLET SUBURBAN
97 Suburban K1500 5.7L 120K: About 40% of the time, it starts sluggishly as though it is not getting enough fuel. Once started, it seems to run fine. A couple of times in the past 4 months it "died:"

-- Once by failing to respond when accelerating from a light (it stayed on and seemed to stay at idle even though the accelerator was being pressed). Shut it off, turned it back on and it was fine. Mechanic found no error codes.

-- Once by stalling as I put it in Park.

-- Last night it would not initially start but seemed to almost "backfire" and then a single puff of smoke came out from the hood. Opened it up, saw no visible signs of where the smoke came from, tried starting again and it started right up. This morning, no problems driving to work in rush hour traffic.

Any ideas would be very appreciated!
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Thursday, November 8th, 2007 AT 9:32 AM

4 Replies

Tiny
PEAR69
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Did you fix this problem?
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Wednesday, November 21st, 2007 AT 11:34 AM
Tiny
MMACARTHUR
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We suspected the fuel pump. However we took the intake manifold off first since we had to do that gasket again anyway and this would allow us to get a good look at the injection system. Noticed leakage at the fuel pressure regulator. Decided to go ahead and replace the whole fuel injector assembly including the rails since it wasn't that much more in cost, and it turns out Chevy has improved the design by putting the injectors closer to the manifold. After doing that, fuel pressure holds up and the truck is running well again. It's only been a few weeks so time will tell for sure.
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Wednesday, November 21st, 2007 AT 12:27 PM
Tiny
PEAR69
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BINGO, I was going to tell you that very thing. I noticed you said you had to change the lower intake gasket again? I hope you used fel-pros' kit. Do not use the GM gasket! If you used a fel-pro kit and this happens again I will suggest changing the entire lower intake manifold to a dorman manifold. Some of these factory manifolds had a casting flaw that warps them very easily. Just a thought. Good luck
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Wednesday, November 21st, 2007 AT 1:14 PM
Tiny
MMACARTHUR
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Yes, I got 65,000 miles out of this intake manifold gasket after about 55,000 on the original. I didn't do the work --- pretty sure my mechanic used the GM gasket but he said they changed the design and it looks pretty bullet proof now. I guess I'll probably know for sure around 60,000 miles from now. Thanks very much for your response and for the tip on the manifold and gasket. I think if I do have to do it again I'll go ahead and switch to the dorman manifold with the fel-pro gasket.

Thanks again!
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Wednesday, November 21st, 2007 AT 2:01 PM

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