Timming in tabs can be very difficult Especially if your using tabs that were typed in a word processor. To get rid of this probelm i would play form tabs that were generated with aprogram such as
Guitar pro. Guitar pro actually spaces the notes to the correct spacing for the timming. So you have to mentally equate the spaces to note lengths etc.
I have difficulty readign while playing as well especially if i dont know the song. Playing a song I know makes it easier. I generally only take guidance from the tabs as to what to play. Then I go for the sound of the original song.