I put a bottle of ARx in my sis n laws car. It's a 2003 Alero V6. I had run a tank of fuel system cleaner thru it and she said it improved. Red flag. The ARx is still in the cleaning stage but MPG went from 24 to 26 so she has benefitted already. She puts 2500 miles on it in a short time all city driving. I still have 2 more bottles left and told her we will do it in another 25k miles.