Need some help

I got a 95 GT and have had a viberation when in D (automatic) at a stop. It is also sluggish.
I´ve changed the plugs, wires, cap and rotor, and timing. Also had a fuel system cleaning before the problem started, maybe it caused more damage than good.
Could it also have something to do with my timing belt being stretched or slipped a tooth.

Dave
95 Scort GT
Not much else...