05 VLX With 340 Engine, Surging Idle

[95echelon]

Hi All, I am struggling with an intermittent issue that popped up before I put the boat away in the fall. It's happening again this spring. At the end of a longer outing (typically pulling a wakeboarder or similar) I come back to put my boat in the lift and the idle will drop quite a bit to nearly a stall and then surge back up to 1100 or more and this just repeats. This obviously makes docking a pain the a** when you have to engage at 1100 rpms and slam a bit into gear. This seems to happen at the end of a run, I have not noticed it for instance on startup or when I take a quick run to the gas pump across the bay.

Could you helpful folks give me some troubleshooting ideas? Engine has almost 1400 hours. Here is what I think I should try:

1. Plugs and fluids are new as of last fall at putaway time.
2. I have owned the boat ~350 hours and have never done cap, rotor and wires so I think that could be a start. Any recommendations on part sourcing?
3. I have heard some say to check the cannon plug.
4. Is there a MAF sensor or similar that I should clean/replace
5. The filter is a K&N that I have never cleaned.
6. I haven't changed the fuel filter since I bought it 3 seasons ago.
7. I have occasionally (maybe 3x) had the boat say low oil pressure then coming down to a stop from high speed. I think this was just being a quart low but others have said to check the cannon plug on this. Could be completely unrelated.

Is there any other troubleshooting I can do before just tossing 500 bucks in parts in and crossing my fingers?

Thanks in advance for any guidance you can provide!

[formulaben]

I would start with IAC valve...weird, posted this like 3 times in the last 3 days, but anyhow super quick check next time it does it, or just pull it now and clean or replace with new.  Mine was under $40 at O'Reilley's IIRC.  Your boat is close enough that tutorial should be pretty close.

 

[95echelon]

Just now, formulaben said:

I would start with IAC valve...weird, posted this like 3 times in the last 3 days, but anyhow super quick check next time it does it, or just pull it now and clean or replace with new.  Mine was under $40 at O'Reilley's IIRC.  Your boat is close enough that tutorial should be pretty close.

 

Thanks! I searched in the fall but I should have searched again.