A mechanic once told me that they run straight injector cleaner through the injectors when a service station cleans injectors. I don't know if this is true, maybe someone else can verify. Personally I believe strongly in Textron brand cleaner. When I cleaned my fuel injection system after reassembling my D, I put a bottle (maybe 2) in the tank with a couple gallons of fuel. I bypassed the pump and ran it until I could hear it return to the fuel tank. I let it sit for a couple days and cycled it again. I ran the car on the higher strength cleaner for a while before diluting the mixture. The car ran fine after that. Of course, your results may vary. NK