I have Marquis that shows error code for all four O2 sensors. Seems odd that all would go bad at same time. I looked for fuse but cannot find what fuse feeds the O2 pre-heat circuit. Looked for bad wire but cannot find one. Has been to two different shops who run scan but then tell me they cannot find the problem. Getting tired of paying for diagnosis with no cure.
I have Marquis that shows error code for all four O2 sensors.
What are the codes? You have not provided mileage either. That information is requested in the posting instructions near the top of the main page.
I looked for fuse but cannot find what fuse feeds the O2 pre-heat circuit.
It should be in your owner's manual if not listed in the fuse block itself.
Looked for bad wire but cannot find one.
Did you test wiring using a continuity tester or ohm meter?
Has been to two different shops who run scan but then tell me they cannot find the problem.
Did they check freeze-frame or live data or just pull codes?
Getting tired of paying for diagnosis with no cure.
Seeing as how the car is 25 years old there could be any number of problems. You need a mechanic who is more capable of diagnostic work.
