Engine putters when accelerating at about 2500 rpms?

my engin putters a little when im exelerating from low rpms i think it migh have somthing to do with trash in the gas but im not sure. any sugestions? Also when i shift gears most the time it goes in easy but some times it is hard and i have to put it in nutral and try again, it is worst when i put it in revers i have to try it a few times what coudl be causing this?

well the puttering would more than likely be timing is off, get a timing light and find out, also find out if the mechanical timing is on, but requires you to take the timing cover on the top off to see. as for the gears goin in hard that might have somehting to do with the idle not being up to par. but maybe something else.