Mine never totally cut off but it was definitely the coil pack. If you have a known good one you can swap out that might help to test the theory. It was such a pain finding a good coil (tested brand new ones at Richards and many were bad) that I'm installing the TR-6 set up from bob bailey as soon as I get the wires.
'87 GN 58K miles (rebuilt engine by Don Cruz at 47K), 6262 Billet Precision Turbo, Precision 60 lbs injectors, 206/210 Revolution X Roller Cam, Comp Roller lifters, Champion Iron Heads, Champion Ported Intake, T&D 1.65 Roller Rockers, 70 mm Hemco Upper Intake, 70 mm Acufab TB, PTC 10" TC 2800 Stall w/LU, Razor's Kit, ESP FMIC, B & M Shift kit, 3" GN1 DP w/46mm external wastegate, 2 3/4" Dual Magna flow exhaust, ATR Headers, 3.5" Kirbans Aluminium Driveshaft, Eibach Pro Kit Springs, Bilstein Shocks, Spohn Boxed Rear Lowers, Spohn Rear Uppers, SD2 Chip, XP Plus Fuel Pump w/hotwire, Turbonetics Boost Controller, Scanmaster, Powerlogger, Hurst Line Lock, MT ET Streets 255/50-16