I've used just about every store bought "cleaner" type product with underwhelming results. Needless to say I went in with low expectations because of that. After using the injector cleaner per instructions and adding the tune up to my gas tank I've noticed a slew of improvements on my vehicle. My mystery miss-fire is gone, smoother idle and acceleration, and I even added a bottle to my transmission and have noticed an improvement in shift points. This stuff works. 205k miles and going strong.