Ok, so my 01 Runner with 150k on the clock is givin me a CEL...after hooking up the scanner it gave me a "lean Mixture/bank 1" with the handy little O2 and Cat lights blinking..Am I correct in guessing its time to swap out o2 sensors?

any input would be greatly appreciatted, as Im needing tabs, and here in lovely Wa state that means its gotta go to the smog shop first.

 

Something else to check, my moms 2000 4runner had something similar (but I am not sure if it was the same code), and it ended up being a MAF sensor. The dealer was the only one that was able to correctly diagnose the problem and fix it.

 

do you happen to know what they did to fix it? cleaning/replacement or just an adjustment?

 

They just replaced it. It was a dealer so they probably don't even bother with cleaning...easier for them to just replace.

 

id say if you have 150,000 miles on them, thats pretty good life span for a emissions state. It may have a small vacuum leak also thats leaning it out, or even a small leak in the exhaust in between o2 sensors can do that. If it was mine id do the o2 sensor 1st