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
No, that should be up around 16 to 18. It appears to be losing vacuum somewhere.
Sunday, June 12th, 2011 AT 9:06 PM
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