Was out a couple of days ago and for abou an hour the engine ran like a stripped tail ape, Had to get a little gas at the marina and it ran fine for another 20 minutes. Pulling up to fish at my spot and at idle the engine died, started right back up but would only run at 1100 rpm's 1105 it would die. Had to do four miles to the ramp at 1100 but it made it with no warnings of any kind. What do you think? Bad gas? O2 sensor? Any thoughts would be greatly appreciated!

Fuel filters, (HPDI's have a bunch) to learn a Ton about HPDI you can search a guy named RodBolt on iboats forum.

If your VST vapor separator filter gets clogged what you experienced can happen.

What would it do when you pushed down on the pedal? Did it feel really rough and wouldn't get over 1100?

I have the same engine and had an issue with a bad TPS (Throttle Position Sensor) so when it was in gear the engine would think it was in neutral and wouldn't be running on all cylinders.

Did you check the primer bulb, was it hard or soft?

Willy, when I pushed the pedal it would just die and not go over 1100rpm though it would start right back up.
Tommy, the primer bulb was hard as a rock.

Thank you CADD I'll have a look.