Sounds like bad injection problem. When was the last time you paid for a whole injection cleanning? If your answer is more than six months or 25000 miles, you better check it before any aditional troubleshooting. Also you may be interested at the same time in a whole tune up (rotor, rotor cap, sparks & wires, gas&air filters) amnn.. not sure if I am overriding anything.
Hope this helps,
MC
