On most vehicles, a bad o2 will cause the chech engine light to come on, decrease in fuel mileage, and varioius runing problems including: surging, running rough, stumbling.....
what year? what motor 8v or 16v the 8v has 1 , right on top of exh.manifold the older (pre 96) has 1 at the exhaust collector. the newer 96+ have 2 , but only the front one controls air fuel ratios....
I just replaced one for a problem that had had me flummoxed. My 95 Plymouth Voyager 3.3 liter drove fine most of the time but on rare occasions wouldn't respond momentarily to the throttle. Also,...