Ricky,

Sounds like you are getting a slight backfire once in a while to blow out the diaphragm. How many hours on lift? Anything over 2000 hours should have spray seafoam pump into the intake system on a warm engine while running to clean carbon off of valves. Shut down and let it sit for about 1 hour. Run engine for about another hour. If you have high hours on lift I would do it twice. The only other system that may affect it is the spark plugs. Should you notice a miss every so often, check harness where it connects to the coils. There have been harness issues in that area. Good Luck.