I have one of these on my rear 02 sensor when I took my cat off(big mistake!!) I put a new cat converter back on the truck and now it runs just fine and sounds alot better.

Anyway, the truck runs like a champ, gets about 21MPG and no CE light. Would the MIL still somehow be affecting the truck in someway? Should I replace the rear 02 sensor or just leave it as is? -Mike-

 

shouldnt have to worry about it..the only thing the rear o2 does is just make sure that there isnt alot of trash coming out of the cat. i would just leave it

 

If your CEL is on it's impairing the vehicle's driving ability. I'd suggest fixing the problem if the light is on and it's telling you there's a problem.

 

hey thanks guys, I just left this thread be after about a week lol! like I said, the truck runs like a champ, no check engine light or anything. -Mike-