i have recently added a gum-out diesel injector cleaner to my tank when i fill up. i don't know if it's my imagination or what, but it seems as though my h1 is running much stronger and smoother than before. i have continually treated each tank for approximately four fill-ups. if it is indeed helping, i thought maybe it might help someone else. it took about two fills before i could tell the difference. i'd be curious if anyone else has had the same result.