1991 Chevy Truck 1991 Chevy Stepside 5.7 Liter Vin-K, Runs

1991 CHEVROLET TRUCK
170,000 MILES • V8 • 2WD • AUTOMATIC
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GOATIS
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  • 3 POSTS
1991 Chevy Stepside 5.7 Liter Vin-K, Runs extremely rough, lacks power, won't accelerate and refuses to idle. My question is why when I run direct vacuum from the TBI to the EGR valve it runs considerably better. What would cause this? Faulty O2, TPS, MAP or some other sensor or is it Ignition or Fuel related? Please help, makes no sense to me at all that with the EGR constantly open that it runs better. Thanks in advance.
Feb 20, 2010 at 6:55 AM
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RASMATAZ
  • ✓Experienced Mechanic
  • 75,988 POSTS
Try cleaning out the idle air control valve and PCV/EGR valves and test the TPS and MAP sensors-to include a fuel pressure check.
Feb 20, 2010 at 9:51 AM
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GOATIS
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  • 3 POSTS
It ended up being the rubber hose that connects the in tank pump to the sending unit, had a split in it and was just dumping the gas right back in the tank. Once fixed the truck refused to run with direct vacume to the egr :) go figure. Thanks again for pointing me in the right direction.
Mar 4, 2010 at 1:53 PM
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