PCM Diagnostics & Tuning - 171/174 Codes




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Roy V.
10-04-2005, 11:33 AM
Going to work yesterday, my car started surging and bucking, wanting to stall when stopped and running like hell. I had to feather the gas to keep it from stalling.

I got two codes - 171 and 174 which appear to be a lean condition, no other codes. Checked the long term fuel trims and both showed up at 24.9, however bank 2 would fluctuate occasionally. Pulled the 02 voltage and could not get it above 120 mV. Diagnostic charts from alldatadiy.com point to something wrong with O2 sensor wiring. I haven't had time to jack up the car to look but I'm curious why both banks would set off lean conditions at the same time. Any thoughts to where I might look for the trouble first?

The car is an 04 GTO and I have Dynatech headers which have been on for 9 months with no previous problems.

Thanks,

Roy


ninobrn99
10-04-2005, 11:12 PM
its an intake problem more than likely. you have a vaccum leak, you just need to find it. has the intake been messed with at all??