I have an 03 f150 with 5.4l. I was getting a lean code p0171. I changed a few vac lines and rest the light. Now i am getting po155 and p1151. Autozone says i need a new o2 is this the right path to take?

 

Maybe, maybe not. Both codes are for bank 2 (driver's side) front sensor. There may be a wiring issue.

https://www.obd-codes.com/p0155
https://www.obd-codes.com/p1151-ford

 

What would be a good place to start on a wiring issue? I have a multimeter is there a diagram for these wires?

I need to get this fixed in the next few weeks as i have a road trip in coming up.
Thanks for the help so far.

 

Well, if you have more than 100k on the engine, I'd replace both front O2's on general principle. Good chance that will fix it. Use only Motorcraft or Bosch sensors.

 

Got just under 165k on it now. But I did replace all 4 with bosh 4-5 years ago. Could a bad o2 show a lean code? I'm just curious as the light was on for a lean which caused me to swap out a few vac lines. I could not see or feel a leak but did replace a few that didn't look in the best shape. After replacement of lines I reset the cel and went for a spin. Light came back on and now these codes popped up.

Wife forced me out of the garage for the day. Had to replace pinion seal this morning and do an oil change and a few other odds and ends. So I won't be back under the truck till tomorrow. The o2 are cheap enough I'll just grab 2 and see what happens.

 

Installed new O2. So far light has not come back on. Thanks for the help.