Hi, David; What you described are classic symptoms of a failing ignitor or ignition control module. Hard to prove, though. You'll have to check to see if you are getting spark from the coil during the 'dead' time. If you are, then it's not the ignitor or the control module. (back to square one).
1991 celica gt-s 2.2 automatic, car starts up great and runs great but after running for 20 mins it will randomly go dead and when you try to start it back up it just cranks, if you let it sit for a few mins it will fire back up like nothing never happened. It doesn't do it all the time but here lately it's got worse. When the car dies while driving, it doesn't sputter or miss, just shuts off, still has power so I know it's not a battery or alternator issue. Also sometimes it drives fine, turn it off, then try to start it back up, and it just cranks til it sits for awhile. It's throwing a code, code is 12. Any help will be greatly appreciated