Have you tried looking for active or pending diagnostic trouble codes using a code reader or scanner?
Do you have '99 Factory Service Manual? If so, refer to Section 8D, Ignition System. Go to the paragraph about installation of the disdributor.
You can check to see if the distributor timing is out of phase with the crankshaft/camshaft by positioning #1 piston at TDC, compression stroke, and the timing index mark on the vibration dampener pointed at the "0" degree mark on the degrees index on the camshaft cover.
At this point, remove the distributor cap and cam sensor. Using a 3/16" drift pin punch or drill, see if the punch/drill will freely enter the alignment hole in the distributor housing. If it does, and the distributor rotor is pointing slightly past the 3 o'clock position (#1 cylinder), the crankshaft/distributor timing is correct. If the punch/drill will not enter the alignment hole the timing is off.
Note that when you are rotating the crankshaft clockwise (starting from cylinder #2 position in the distributor) and get close to get to the "0" timing mark on the cam cover, the rotor will enter the #1 cylinder position distributor cap terminal before you reach the "0" mark, and go past it a bit after you get to the "0" timing mark.
Check this out and get back.
