Car runs outstanding then horrible. Also sometimes hard starting.
Replaced cap, rotor, wires, plugs, fuel filter, air filter, then checked
ignition timing. Timing good when engine runs good, advance not very
responsive when engine runs bad. Also erratic spark when running poorly.
After disconnecting the EST bypass wire to prevent advance while checking
base timing, (jumping terminals A and B advances the timing)then
reconnecting wire, shutting engine off and restarting, drivability is once
again fantastic but doesn't last.  It looses power, hesitates, and
sometimes stalls.  When hard starting exists excessive cranking is
necessary.  Cant check fuel pressure do to damaged schrader valve.
   Any suggestions will be greatly appreciated.