i use lucas fuel injection cleaner in my benzs and it does a great job. buy it at mejers $6.89 or auto zone or advanced $8.99. also for lubricant i heard of putting a half quart of transmision oil in fuel tank. a friend of mine has a $250,000 motorhome and he puts is used motor oil in his diesel engine about a quart at a time to 75 gallons of diesel. havn't tried that yet!