Update on this-
Dealer replaced the other 3 O2 sensors. Also found a leak from the valve cover into one of the sensors, said that the leak may have caused a short in wiring. No CEL or ESS lights, mpg is back up. They also said that the P300 was caused by the o2 sensor problems.
We keep all the dealer records, but I'll start keeping photos as well. Hopefully they can figure out the problem- We love the truck, but I didnt expect my renix jeep to be more reliable!
Fiance's 2021 Gladiator just went back to the dealer for the second time in a week (First time it threw a bunch of O2/lean condition codes). Second time was the P0300. I'll include the first codes since it happened less than 20 miles apart.
Build date: 8/26/2020
Mileage when it first...