[NoDOHC]

Back from the dead... It turns out that it was a combination of the fuel pressure regulator and another leaking injector. Since I already had the car in the garage (quite an undertaking since it refused to do anything but idle for the entire event), I went ahead and built another engine for in it (higher compression rotors) and replaced everything on the fuel system. The fuel pressure was starting at about 35 psi (running) and then it would intermittently drop out. It was completely random, I figured that it was the fuel pump, but pinching the return line with a pair of vise-grip pliers got the fuel pressure right up to where it should be (thus implicating the fuel pressure regulator).

I think that my very old fuel filter gave up the ghost from the E85 and the debris that it had caught over the last ??? years all got through and ruined my first injector and later the fuel pressure regulator. It turns out that I had a second leaking injector too, which explains the conflicting symptoms.

The FPR and all 4 injectors were replaced and no more problems!