interstate cel help

[mach1460]

whenever i drive my x in town its great, no probs, but as soon as i get on the interstate and cruze for and hour or so my cel comes on. I hoped out and used my gay little obd1 ford code puller and its reads 176 (heated oxygen sensor indicates lean condition, left side) I put in a new oxtgen sensor and it still comes on if i get on the interstate!!!!! do i need to clear the code somehow or could my new o2 be defaulty cause my gas mileage stayed about the same with the new o2???

 

[Alec]

Try cleaning the MAS.

 

[MrShorty]

Could be a bad O2 sensor. But it could also be several other things. MAF has already been mentioned, clogged fuel injectors/low fuel pressure, bad connection between O2 sensor and computer, etc.