4.3L 2000 Sierra hesitation/no start

Almost like clockwork as soon as I rolled over 125,000miles it begun. Started out with some bad hesitation until finally It wouldnt start. It cranks but wont fire, pretty strong smell of gas as well. If it sits a few days 3-4 it'll fire up after a little coaxing.

Smelled the dipstick and it had a very strong odor of gas. Thinking I had a leak I eventually got down into the upper intake and there was a nice little glistening pool of gasoline sitting on the intake right below the pressure regulator (#6 cylinder I believe)

I've checked/replaced most of the regular items (60-61psi from the pump) and wont be able to get to the auto store until later this week, but could that little puddle be the cause of my hesitation/no start woes?

I did get the following codes as well

P0420 Catalyst System Efficiency Below Threshold (Bank 1)

P0300 Random/Multiple Cylinder Misfire Detected