O2 sensor?

Check engine light is on. Cleaned the MAF and reset the code by disconnecting the battery for 10 min. The light stayed off for a day then came back on. The truck is running poorly if you get into the throttle. Code thrown is too lean in bank one. Think its the O2? Would that cause it to run poorly?

 

Don't know what would be causing it to run poorly but it could be a bad cat

 

Up stream o2 sensor. I've had mine go bad. My 04 had no power at all and would drink fuel like a fish

 

Does the bank 1 code mean its upstream? Where is the best place to buy a new Denso sensor? The truck runs fine at low rpm, but when you mash on the gas, the truck spits and sputters (backfired once). Im thinking it may be the sensor.

 

If your engine is sputtering and backfiring, and the code is a lean code, I would look more towards a vacuum leak off-idle (ported vacuum) or something along those lines. Maybe even a fuel supply issue (Which would cause a lean code as well) The bank 1 A/F sensor IS upstream, so it is the closest one to the engine.