I had a 1992 Toy 6 cyl 4x4 x cab with a manual trannie p/u that I purchased new , at 400 miles I changed the oil with dino and again at 1,000 miles to syn, then on ran amsoil ,M1,or Redline changed at 1 year intervals and was more or less 9,000 miles per year. With the valve covers off the engine looked like it never had beed fired up it was immaculate. at 85,000 miles [after reading the A R/X results on Bob is the Oil Guy I tried it] Immediatly after pouring in the A R/X and going to the store about 18 mile round trip the engine seemen to idle smoother and after the 2,000 mile clean I cut open the filter and there was a few specs of Black powder in the pleats and after the rinse a little more of the black powder in the pleats . The results that impressed me was the idle was smoother and the gas milage increased back up to like when it has 15 to 25,000 miles . The mpg increase was about 2 mpgs .I would always seem to get almost 21 mpgs on trips then it dropped to 19 per gallon on summer gas then stayed at the almost 21 mpgs untill it got rear ended and totalled with about 120,000 miles on the odometer. I really liked the truck and was heartbroken to loose it. I replaced it with a 2006 4 cyl same truck and in all honestly I do not care as much for the 2006 as compared to the 1992 but I really like the 4 cyl engine as it gets about 3 + mpgs better overall and the motor has more power if you work the engine over the 6 cyl.[3litre]P.S.it cleans up the carbon deposits and what ever.