joejeep is right, except you can get it at just about any parts store. You put it in either your throttle body, brake booster vacume line, oil, gas, or whatever you want to clean. if its going in your motor, let it set for bout an hour, and start it up. Depending on how dirty your engine is, give it 2 or 3 doses.
my jeep has the confused prerunner syndrome....4.5" in the rear and 2" in the front.
Purple Jeep Club Member # 1