Okay long story short brand new 350 with 350hp brand new tranny in a 2 door Tahoe with 6 inches of lift on 33s. I went on my first long trip with the truck which was only 40 miles from my shop to my house and it struggled to get up hills it down shifted like it was supposed too but it was still a struggle. I am throwing o2 codes but that would just make me run rich which it is doing. What are other options? It still has factory gears but that shouldn't matter being as I only put 33s on it. Its a 94 Tahoe.