I tried everything I could think of including sealing the engine, new fuel lines, etc. and still was getting occasional flame outs at random intervals, but usually after the tank was at least half empty. I checked the tank in a sink full of water, blew air into it and no leaks.
Just for the heck of it I bought a new stock NTC3 tank for $10 to replace the K Factory Low CG tank that was on there. And presto, problem gone!
I could not find any leaks so maybe there was something clogging the pickup in the old tank or some other issue but clearly it was the tank giving me all these headaches! Now it runs flawlessly from the beginning of the tank all the way to the last drop!