2012 Df20a Rough running/sounding while in gear but smooth at idle

[flyfshrmn82]

I have a 2012 with about 90hrs that has been amazing. This past weekend I went camping and ran into an issue. It ran fine then suddenly lost power and started running very rough and died. No red light errors. I got it started again and it would idle in neutral, but when I put it in gear and gave a little gas it grumbled, sputtered and died. Thinking it could be a gas related issue (I always run E-free gas in my engine and the current gas was about 6weeks old and had been treated with startron), I swapped the tanks (new gas from the ramp that I bought about an hour ago) and ran it in idle for about 3-4 minutes to get the new fuel into the system. It sounds different when in gear and continued to lack any throttle response, plus it doesn't start on the first pull anymore. It takes 3-4 hard pulls before it barely starts. Then it takes a few seconds of rough idling before it starts to smooth out and sound normal (in neutral).

I inspected plugs (which only have about 10hrs on them and fuel line with no findings. Does this sound familiar to anyone? Anything I can try to troubleshoot myself before having to take it to a dealer?

[Solarman]

df20, 2012, running issues

Do you have a manual for your motor?
If so check the map sensor and its opening, it may be blocked, or dirty.
Did you notice if fuel bulb was collapsed, or try to pump it, to see if it made any difference? Can you tell if high pressure fuel pump is working (hear it)?
Check neutral switch (loose wires), kill switch (loose wires)? Any signs of corrosion on any wires on motor? Check other connections on motor.
Has motor ever been serviced by a dealer?

Post us if you notice anything.

[flyfshrmn82]

I have the manual, and I did check and clean the MAP sensor. The fuel system checked out. No issues with the tank venting, bulbs collapsing, bad lines/connectors or dirty fuel. The spark plugs were practically new with 10hrs on them (at $10ea they should be good). Once I got home I performed a cylinder cut out test (unplug one injector at a time) and found one cylinder not working. Excited to diagnose it down to one cylinder, I took it into the shop after that. I figured it was an injector or a coil causing the engine to run on only 1 cylinder.

Once at the shop I told them what step I did. They asked it I had switched the plugs to see if the problem followed the plugs... I should have gone one step further... $115 dollars later I had 2 new spark plugs in the engine and 2 extra spark plugs in the boat box. I learned that spark plugs can be unreliable no matter how new they are...

[Solarman]

Thanx for the update. Honestly I would not have thought plugs either. Even knowing how new plugs can be bad.