Sure sounds like a fuel supply problem. I would check the fuel pump first. Warm up the engine and get it to its failure point. Then operate the hand pump and see if you get a "buzzing" sound that would indicate it is functioning. If it is working OK, your problem might be in the IP. You did say that the filters are new, but you might try back flushing the fuel supply lines to make sure they aren't plugged. If that solves the problem temporarily you should probably drain and clean the tank.

Just suggestions. Others will jump in with more I'm sure.