WHY DOES 1997 CHEVY TAHOE RUN FINE AT IDLE-BUT BACKFIRES, AND RUNS ROUGH WHILE DRIVING?

  • Tiny
  • debohallo
  • 1997 Chevrolet Tahoe
  • 176,000 miles

Cannot go over 20 mph or it will bog down and die out. We replaced the fuel filter, plugs, plug wires, and upper crank position sensor. We also had the ignition control module tested and it checked out good. We ran some seafoam through because water was coming out of exhaust. Nothing has made a difference-please tell me what to try next?

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Tuesday, February 21st, 2012 AT 12:20 AM

12 Replies

  • Tiny
  • billymac
  • Expert
  • 2,240 posts

Two possibilities fuel pump or timeing chain. I would check these both.

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Tuesday, February 21st, 2012 AT 12:24 AM
  • Tiny
  • debohallo
  • Member

Can you tell me how to check both?

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Tuesday, February 21st, 2012 AT 12:26 AM
  • Tiny
  • debohallo
  • Member

Because it runs well at idle I did not think fuel pump

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Tuesday, February 21st, 2012 AT 12:27 AM
  • Tiny
  • debohallo
  • Member

I just asked-and the fuel pressure was checked while the vehicle was running-and it was 60 lbs pressure

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Tuesday, February 21st, 2012 AT 12:31 AM
  • Tiny
  • billymac
  • Expert
  • 2,240 posts

Yes but it requires less fuel delivery at idle when you accelerate more volume is required the bogg and backfire together really to me seems like fuel delivery prob. This is just something that should be checked not common for a fuel pump to act this way, but I have seen it.

Another possibility is a restricted exhaust system

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Tuesday, February 21st, 2012 AT 12:32 AM
  • Tiny
  • debohallo
  • Member

Do you think it could be the distributor cap?

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Tuesday, February 21st, 2012 AT 1:00 AM
  • Tiny
  • billymac
  • Expert
  • 2,240 posts

Yes it is a possibility that the distributor cap or rotor has failed cracked I thought you had tuned it up sorry my mistake. So fuel pressure is ok now we have to believe it is electrical I would replace that cap and rotor so it can be eliminated.

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Tuesday, February 21st, 2012 AT 1:04 AM
  • Tiny
  • debohallo
  • Member

We did replace the rotor-not the distributor cap. Today we replaced the crank position sensor-the first one we replaced was the cam position sensor. It seems to have more power-but still backfires. There is a lot of condensation coming from the exhaust-even though we previously ran seafoam through it

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Wednesday, February 22nd, 2012 AT 12:05 AM
  • Tiny
  • debohallo
  • Member

The code is P1345-which is cam sensor/crank sensor correlation-but both of the sensors are new

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Wednesday, February 22nd, 2012 AT 12:07 AM
  • Tiny
  • billymac
  • Expert
  • 2,240 posts

This sounds like a timeing chain. Olease repost your question and hopefully our gm guys can help

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Wednesday, February 22nd, 2012 AT 12:35 AM

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