im not sure on the Correct stock timing, but i would check your timimg.....if its fine then it could be valve clearances or sticking valves, in that case you would have to take the head off and get it decarbonized.....

since you said you replaced the plugs/wires i dont think your insulators for the plugs are faulty....did you gap them correctly?

your fuel injectors, intake mani could also have a vaccum leak....

and yeah, the coil is in the distrib assy.