In my quest to fix my rough engine with rotten low speed driveability I took note of the buildup around the injector at cylinder 3. Notice the flare of brown oily buildup coming from the port:

as opposed to cylinder port number one:


now look at the injector O ring: More than 1 injector had messed up O rings:


It no doubt was sucking air while the engine was on and blowing hot vapors out - which I noticed- while the engine was cooling.

While I'm on this I had fun "professionally" cleaning my injectors. If you google youtube on this there are vids of guys who have done it this way. A 5 or 6 cc syringe does NOT work - too small. I twisted the end off a used silicone sealer then pulled the hardened silicone out and nipped the end off the silicone to remain as a plug. I pierced my straw through this. I found a 9volt 300ma charger and placed two alligator clips on the ends. by turning the power strip on it activated the injector and I pressure squirted carb cleaner through them.


all clean:


and ready for new O rings.