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1995 f150 5.0 4wd auto tranny.On the way home from work this morning,the check engine light came on for about 5 seconds,then went back off. truck was running fine,engine didn't stumble or anything. I pulled the codes and got code 181,which according to book I have that came with my code reader means: TRUCKS ONLY HEGO(H02S) sensor fault unable to switch/lean during part throttle. but on fordfuelinjection.com it says code 181 means Right side still lean, at richest adaptive limit, during part throttle. which one is correct,and what does it mean? my oxygen sensor going bad? thanks for any info!!
Both definitions are sorta saying the same thing, the motor is running lean and the O2 sensor is not switching.. which it won't do unless the A/F mixture is near 14.7:1. This is not necessarily an O2 sensor problem, more likely something else, I suggest you drive it for a while and keep an eye on the milage and see if any other codes come up.
thanks Paul. I wasn't planning on changing the o2 sensor right away,was going to keep my eye on it to see if something else came up. was just kind of wondering why whatever caused the engine light to come on didn't affect the running of the engine,i wouldn't even have known the light was on if I hadn't just happened to be glancing at the gauges when it happened.