1999 GMC Suburban No power

1999 GMC SUBURBAN
176,000 MILES • V8 • 4WD • AUTOMATIC
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DSVOLDEN
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  • 3 POSTS
My 99 GMC suburban has no power. If you push the gas pedal down it will not go. If you let up, it will accelerate slowly. The codes that came up are P0131 and P1870. Where would I start?
Mar 16, 2009 at 11:11 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Sounds like a transmission slipping problem. Check level and condition of the fluid if it continues get it pressure tested.

Also check and test the throttle position sensor
Mar 16, 2009 at 12:04 PM
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DSVOLDEN
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I forgot to mention that when it's cold outside, it runs good. Do you think it could be the O2 sensor?
Mar 16, 2009 at 11:53 PM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Could be it came up with P0131
Mar 17, 2009 at 7:01 AM
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DSVOLDEN
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ok, I know it's been awhile. I changed the transmission and it ran ok for a month or so. Now, it is losing power again. Exactly the same way. New throttle position sensor, MAf sensor. Any ideas?
Jun 12, 2010 at 12:27 AM
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SWSIMONTON
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it was transmission fault it has nothing do to engine. i had same problem it was shift solienod problem when i put in 1 gear got power when i shift to 2 at 30 mph took long time to chaange in 2 gear so i has change all solienod inside pan of transmissin finilly got shift correct at start .. got horsepower back normal.. pain in ass !
Apr 9, 2013 at 4:29 PM
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