Rough Country Performance Chips

I installed this yesterday and took a trip of a little over six hundred miles Truck actually goes into eighth gear now. Had a three-mile-per-hour gain in gas mileage. Was not expecting the gas mileage change I had to tweak the tire size. I have thirty fives on my truck but finally got the speedometer set at thirty-three and a quarter on tire size I checked it against satellite so it's really close. I also had some codes on my truck and it cleared them for me at my request I did write them down just in case I get them again. I Will look them up later I was wanting to change my gear ratio and this device will actually let me program it to new gears after I have it done. Bonus overall I am very pleased with this purchase