Just some background as not sure if this all might be related. Was getting a p0449, so i replaced the evap vent solenoid, ACDelco 23103351 and ACDelco 19257603. reset the computer by disconnecting battery term. check engine light out for about a week, pops up again figured it would be the same code, but came up p0138 o2 sensor b1 s2 high volt, and p2271 02 sensor signal stuck high rich b1s2. Now before i go replacing the driver side downflow o2 sensor, acdelco 213-4229, could it be something else, i hate throwing parts at stuff.

Thanks, Dave F.

Heres the vin if u might need it 2GCEK13M881153035.

 

Just wondering if these issues could be fuel related, I've been using wawa (convience station in the northeast) gas for a couple of months, which is not tier 1, should i switch? also should note that the truck has 89,000 miles on it, and should probably tune it up.

 

if it was fuel related it would effect both banks not just one. Inspect the rear 02 sensor wiring for chaffing on the frame.