could also have water in the tank or from all this rain
go to shell or sunoco AFTER u replace the fuel filter and fill it premium. it should help clean out

 

Change out your plugs and wires.

 

check your plugs, wires , vacuum lines, fuel pressure , fuel filter. Hesitation is typically lack of fuel or spark issues.. It could also be the timing.. I just traced out a similar issue with a backfire at high rshared_pm and it turned out to be one plug was fubared.