same problem im having the same problem with my 89 5.0. ive changed my throttle positioning sensor, mass air flow meter, air control valve, and even the ecm. spark plugs are new, but it acts like its misfiring...have to buy new starter now, and ill let u know if that fixes it because i wont know for sure if the ecm fixed it or not. if u hear anything on this issue please let me know. i would also try to adjust the timing...mine did a little better after i did so, but i think my ecm was throwing it off still |