Mechanics

WHAT CAN CAUSE P0171 BUT O2 SENSOR 1 HAS HIGH VOLTS WHEN UNPLUGGED?

2003 Subaru WRX • 75,000 miles

I have a 2003 subaru impreza wrx. Recently it has started running really bad and the P0171 code was on along with the P0031. I replaced both 02 sensors, fuel filter, cleaned the MAF sensor. The only code showing now is P0171 which means it is running lean but the voltage of o2 sensor 1 bank 1 is really high around 3.7 V. The car runs a little better but still hesitates when trying to get up to speed. I have no idea what could be causing it.
Avatar
Hass2b
April 1, 2012.




171 is a vacuum leak. It could be a bad hose, mass air flow, pcv valve, low fuel pressure or the big air hose to the throttle body has a hole in it.

Roy



AD