If you are looking for a fuel additive, we recommend either Berryman B-12 Total Fuel-System Cleanup (part #2616), or Berryman B-60 High Mileage Fuel System Rejuvenator (part #7516).  Both of these products contain our highest detergent package available and witll thoroughly clean the the entire fuel system, including the intake valves. 7516 is designed with high mileage vehicles in mind. For more dramatic results, and to clean the intake valves and combustion chambers, you can use Berryman Intake Valve & Combustion Chamber Cleaner (part #2611)