troubleshooting GM trouble codes

2002 CHEVROLET AVALANCHE
138,000 MILES • V8 • 4WD • AUTOMATIC
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SKIRACER1
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  • 1 POST
trouble codes PO131 & PO151 banks 1&2 O2 sensors #1 keep setting a trouble code while hwy driving. Also sets pending codes for the #2 O2 sensors on both banks. I replaced both #1 sensors w/ new OE sensors but codes still come on with heavy accelaration on hwy. Also seems to lack power unless under full throttle. Can you help me with a diagnosis? this is a 2002 chevy avalanche 4x4 w/5.3 liter. It was also recently setting a code for the MAF but I cleaned it and the code has not returned.
Feb 23, 2011 at 11:06 PM
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HMAC300
  • ✓ASE Certified Mechanic
  • 48,601 POSTS
  • ASE Certified Mechanic
if you have that code, check your fuel pressure. It should be 55-61 psi. then checkyour fuel regulator. Clane the throttle plate with chokecleaner on both sides as they gum up. Also check for a vacuuum leak. check all hoses air and breather elements for having holes or not connected. these can also set codes.
Mar 15, 2011 at 11:06 PM
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