the lucas product does work if you use it right. my son-n-law who is a master tech at the local gm dealer explained the process to me and how to get results. first buy the quart of lucas cleaner, add the correct amount to your tank of fresh fuel. run the tank as low as you can then fill up and add another treatment of cleaner to it. run the tank out and repete the process but also change your fuel filter. the lucas and other tratments will clean your gas tank and all that crap ends up in your filter. repete the treatment until the quart is gone and then change fuel filter again. after this treat once a month or more often if you are high mile driver for prevention. now i know for a fact this works or it did for me. the test was on my 96 grand prix w/170,000 miles on her. never had the injectors cleaned. after going thru this process total tank miles went from in the 390's to in the 420's.