Direction Injection carbon cleaning – If you have a BMW (135, 335, 535) or Audi with direct injection you may experience rough running and the dreaded Check Engine light.  Direct injection has its benefits but one drawback is that the fuel isn’t sprayed onto the intake valves like in a normal engine so there isn’t any cleaning effect of the fuel’s detergent to keep carbon from building up on the intake valves.  We have the BMW Factory tool that uses finely crushed walnut shells to safely blast this carbon buildup out of your engine.  It works great on Audis, too.