Got frustrated numerous times also..
1.Changed plugs to cooper ngk or denso. gapped mine 28-32. out of the box.
2.Upgraded to an MSD-6AL
3.Magnecor wires
4.Epoxy-msd-black coil
5.cleaned and changed ignition coil in distributor-.
6.checked every hose and elcetrical connection in engine copartment..chked battery/fuses/wur/etc..etc.. output..using a voltmeter...
clean connections--front/rear-fuses.
Get yourself a comfortable chair while doing this...u will get there, but it takes time..
Recently, I developed problems..Changed plugs and clamped down tighter fittings to both intercooler hoses and air intake canister..ALL GOOD
Also--chk your AFR'S maybe to rich or lean...on cruz...etc..etc..
I do an italian tune-up..MMO-2-3 ounces with 10-11 gallons/gas-93
GL
Walt