Them little blue things squeezed all over your wires, t-taps- get rid of them. The scurge of all electrical systems. There is no way to seal them and they create a break point.
Buying an old car is like a box of chocolates....you never know what you got til you bite into it. Yeah, those taps and the spliced wires covered in electrical tape coming out of the ECU are suspects until checked out and preferably eliminated. Places like Mancini Racing and probably NAPA sell new ECU connectors with leads that would help you out a lot. If you go by the connection diagrams posted here, it wouldn't be hard to rewire with solid connections. If it was me, they'd be soldered with shrink tubing for insulation.
You must have a clear fuel filter and the air bubble you see is pretty normal. It seems to me the filter never seems to get 100% filled with fuel. I used a plastic clear filter when I fired up my 225 just to verify I was getting gas and later replaced it with a stock looking metal-bodied one. Air bubble or not, mine runs great and so will yours once you get this problem fixed.
