Just finished the 5" TBE H&S Delete on my 6.7. Mileage a definite improvement...but awful tough to keep my foot out of it. Hard to believe a truck with 37's will lay a hundred foot blackie!!! I'm running the updated box from H&S that doesn't require the EGT probes in the pipe. I keep tripping a P0031 code for low voltage on the O2 sensor. Has anyone seen a fix for this. I unclicked the O2 sensors and put some dielectric grease in them. Didn't fix it!