Engine sputters after coming off plane

[350mpi Guy]

2004 Merc 350 MPI
Alpha One Gen II

After cruising around 3000 RPM, I pull back to neutral and the engine drops from it's normal idle of 600 RPM to 350 RPM. After 45 seconds to a minute the engine jumps back to 600 RPM. I have run two tanks of gas through the tank since summerizing.

Could it be spark plugs, fuel pump, maybe poor quality fuel/ water in fuel?

I did not replace the spark plugs this spring because after removing them to spray fogging agent they seemed in great shape.

 

[AZSenza]

Re: Engine sputters after coming off plane

Spark plugs are cheap, I'd start there, check the cap for corrosion. Was it running good at 3000? normally spark issues show up at higher RPM's as they cant handle the load. Sounds more like a fuel problem to me, how's your fuel/water filter? You'd be suprised how much water you can get from 1 bad fill up.

 

[Lyle29464]

Re: Engine sputters after coming off plane

Interrupter switch sticking?