it sounds like your left hand is dragging a little bit.
just think 1e+a 2e+a ...
try doing 16th notes slowly but with the double sticking (RR LL)

hope this helps

I'll give that a shot... Sometimes the simple things are what counts..

Play a repetitive drum pattern (ex. basic rock beat) and focus on the double taps of the left hand. To do this, play 2 notes (2e) and on the 4, instead play (4e). Now play the pattern. Instead of playing one stroke for the 2 and 4, play an eight note followed by a sixteeth note next to it. It should sound like this.

1 2e 3 4e. and repeat that. Or just do: 1e 2e 3e 4e, from a repetitve drum pattern.

If that doesn't work. Try the Push-Pull technique slowly and then gradually increase the tempo and add in the right hand playing doubles with it. If that doesn't work. I don't know what else to do.