The pressurized cleaners (I used Dupont) work great. You need to be careful as they are sold for professional use only for good reason. Not only will they remove paint and cause blindness, but also if you let it get back to the tank (via the fuel return) it will eat away at you gas tank lining. Before trying injector cleaner, remove your coil pack and inspect the condition of the contacts inside the towers. Make sure they are all nice and shinny. Running around with a wrong plug or plug gap can cause the contacts to turn gray and cause misfires. I had to clean my 3 and 4 tower to fix an intermittent 303 code a few weeks ago.
jeff
