i have a motocraft two barrel carb on a 1979 ford f150 the truck idles good but on exeleration it hestitates and sputters until the rpms build up i took the carb apart and found that one of the jets isnt spraying properly i asked my stock car racing buddy whos a carburator nut and he said thats not my problem i need to check my timing. .... is this true? it doesnt backfire or anything like timing