79 s fire 1500

[rbonilla@holly.ColoState.EDU]

I am fixing up a 1979 spitfire with electronic ignition. The power curve
seems fine on the low end, however, as I run up through 4k (and above)
the power becomes intermittent. It almost seems as if it is missing. I have
adj the valves, replaced the plugs, roter, dist cap, regular unleaded fuel
w/supreme and still get the hesitation or miss. Any ideas out there. Could
this be mixture related? Is there any timing or vacuum advance related 
items to analyze ?? thank you...Richard Bonilla..