BUP

iTrader: (9)

Old and or bad fuel can set your knock sensor faults so look for them while scanning the motor especially running it. Also IMO I think you might had some water in the gas and run it thru the engine. That's why I posted condition of the fuel ?

Also RVP of the fuel itself. RVP = REID VAPOR PRESSURE can fool the best tech in the world trying to pin point engine problems. Fuel for many years has different blends for the changing seasons especially in the North and here in Texas.

Winter blended fuel is totally different than hot summer blended fuel because they have different RVP values. There is RVP testers out on the market if your a serious tuner / mechanic / drag racer along with specific gravity testers for fuel.

A lot of Tuners like for example NHRA Pro Stock engines will test the fuel blends that day at the track to fine tune their air / fuel mixtures thru out the day and changing weather conditions thru out the day. Also as fuel sits it loses its octane rating and has better chances of collecting water even non ethanol gas will collect water in a boat from condensation off the top of the inside gas tank. All boats persay have open fuel vent system which also can lead to condensation build up in the fuel tank.