take your timing light, check timing. rev, see if advancing, put to spec of its not there 5deg -diag.connector jumped-, ~12 unjumped.
next put the timing light on each wire, rev to ~2000 rpm and hold it
watch light for ignition misfires
move on to next wire.

if you have an ignition misfire look at the distro cap, rotor, wires, and grounds.
its possible the coil/igniter has problems at higher rpms. only test is replace with a known good unit.

85 runner -dual cases, headlight harness, 34" TSL's
86 toy buggy getting sas'ed with a 14 bolt rear - 8.5" 10 bolt front (this will go away when i find a 60)