Recently purchased this car broke down as a project to fix up myself, the only codes it’s showing is the heater circuit low for all 4 O2 sensors. I replaced the sensors, and the same codes are still present after clearing. I have tested for voltage, done pin to pin test for continuity, everything seems to check out. I read the wiring diagrams and the upstream and downstream sensors look to be completely separate including the ground location. There also doesn’t seem to be any fuses associated with the sensors.
The car stalls out usually within a minute of running and sometimes will level out and run. I have read the fuel trim and when it first started it starts at 0 and just slowly falls to -32 and shuts off. I tried unplugging the sensors to see if it would run and it did for a couple days then started stalling again, when looking at the fuel trim it was now doing the exact opposite and was a positive fuel trim and slowly stalled out. With the sensors plugged back in it switched back to a negative fuel trim. The MAP reading also seems a little low it reads about 11” at idle
Before I drop the money on a new PCM is there anything else that could cause this issue? And if I do need to go the PCM route, what is the best option? junkyard, pre-programmed, or should I just take it to a mechanic?
The car stalls out usually within a minute of running and sometimes will level out and run. I have read the fuel trim and when it first started it starts at 0 and just slowly falls to -32 and shuts off. I tried unplugging the sensors to see if it would run and it did for a couple days then started stalling again, when looking at the fuel trim it was now doing the exact opposite and was a positive fuel trim and slowly stalled out. With the sensors plugged back in it switched back to a negative fuel trim. The MAP reading also seems a little low it reads about 11” at idle
Before I drop the money on a new PCM is there anything else that could cause this issue? And if I do need to go the PCM route, what is the best option? junkyard, pre-programmed, or should I just take it to a mechanic?
Jul 5, 2023 at 5:22 PM
