[djb383]

Once the Seafoam passes thru the injectors it enters the air intake system, along with fuel, just like when you let the intake vacuum pull it into the intake thru the brake booster hose. From there, the air/fuel/Seafoam mixture enters the combustion chamber. The method you used is basically for old engines that have a heavy carbon build up so you can hit it with a heavy concentration of cleaner. Engine revs must be kept well above idle speed when adding directly to the intake or else the engine will stall and/or plugs will be fouled. If you introduce the Seafoam thru the tank, it still enters the combustion chamber but in a lower concentration. Again, no way these lean running engines will carbon up after only 20K miles.