The fuel level in the car was low at the time of the misfire. Under the 1/8 mark so I added a can of injector cleaner which would be a high percentage compared to a full tank. Anyway was watching the analyzer (Autotap) and observing parameters and clearing the code but then it didn't come back. The flashing check engine light and the code had been coming on all week immediately after clearing it. I threw up a misfire gauge on Autotap which had always been maxed on cylinder 5 and nothing. No counts. Was it the injector and the idling with the cleaner cleared it maybe. The pressurized injector cleaner I bought on Amazon (OTC) requires an adapter for the GM fuel test port so had to buy that and it will arrive later this week and I can blast the real cleaner through the injectors. I may change the plug wires while I'm at it. I'm the second owner of this car and the prior had the lower manifold gaskets replaced around 60K. The car has 125K now. The number 5 plug actually has a little bit of gray material on the electrode and dry. The Hg reading in Autotap is stable at 10.3in-hg which at sea level would be around 15in-hg. I'm at 5000 ft.