I have a 97 Lumina that is throwing 4 codes. I took it to AutoZone and they gave me this...
P0140 - The PCM has determined that there is insufficient activity from oxygen sensor 2 in bank 1.
P0141 - The PCM has determined that a malfunction exists in the heater circuit for oxygen sensor 2 in bank 1.
P0300 - The PCM has determined that multiple random misfires have occurred.
P0401 - The PCM has determined that there is insufficient flow in the exhaust gas recirculation system.
The employee quoted me a price for two O2 sensors, and said that that could be what was causing the random misfires. Reading the receipts it looks to me that only one of my O2 sensors is out. It seems to run fine except when I accelerate hard. Any thoughts / help is welcome. I'm wondering where O2 sensor 2 in bank 1 is, and if the EGR problem could be causing the problem with the O2 sensor? I'm pressed for money right now, and was wondering if I could get away with not replacing the EGR valve? Give me your thoughts please asap. Thank you!