Great discussion on compression testing.
You might be looking at nothing more than a vacuum leak though. Look real close at all the rubber parts, especially the hoses/connections, the injector seals (spraying quick-start or similar to find vacuum leaks works for me), and the large air chamber piece at the front. Mine had several broken hoses and a crack in this piece when I got it home. Silicone worked to seal the air chamber inlet (until I can replace), and some fresh hoses, it idled 60% better. I tested and cleaned the idle air valve, and put in a used but correct part control box to cure the other 38%.
Back to compression, how do you 'ground' the high tension lead from the distributor? Would just disconnecting it hurt the electronics?

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1986 560SL
2002 Toyota Camry
1993 Lexus