CHECK ENGINE LIGHT

  • Tiny
  • promethius
  • 2004 Chevrolet Epica
  • 6 CYL
  • 2WD
  • automatic
  • 42,000 miles

My chevy epica will not pass emissions testing due to po171/174 error codes many people have suggested a vacuum leak could be the cause the frame by frame report showed 11.25 hg at the map is this normal

Sunday, June 12th, 2011 AT 7:58 PM

3 Answers

  • Tiny
  • Wrenchtech
  • Expert
  • 19,836 posts

No, that should be up around 16 to 18. It appears to be losing vacuum somewhere.

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Sunday, June 12th, 2011 AT 9:06 PM
  • Tiny
  • promethius
  • Member

I have replaced the pcv valve, ihave tested the vacuum with a gauge and read in the green, ihave also sprayed maf sensor cleaner everywhere with no change in rpm, I did a second scan today and the coolant temp read 107.60f identical to the previous scan and I made sure that the engine got up to temperatureanc the coolant was circulating

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Sunday, June 12th, 2011 AT 9:57 PM
  • Tiny
  • Wrenchtech
  • Expert
  • 19,836 posts

Sounds like you need some professional help.

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Sunday, June 12th, 2011 AT 10:04 PM

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