GT40 hesitating / sputtering out around 25-30mph

[CheeseSteak1]

I’m have issues with my 1996 ski nautique. If I accelerate too quickly the engine starts hesitating or sputtering. If I accelerate slowly it does it again around 25-30 mph. RPMs are around 2600 when it does it. I just bought the boat and it has 2 speedometers and I don’t know which one is correct. The check engine light is on and I’ve changed out the plugs, cleaned the flame arrestor and replaced the knock sensor. Thoughts on where I should look next? Thanks

[Jonny Quest]

I would look at the following:
- FCC filter
- HP fuel pump
- LP fuel pump
- Injectors
- Fuel pressure regulator
- Distributor cap/rotor

You can use the GPS speedometer on your "smart" phone to compare with the 2 AirGuide speedos in the boat. The speedos can be adjusted using the dial located at the 6 o'clock position on the gauge.

JQ

[mpost]

If your check engine light is on all the time fix this first. The CEL should be on when you turn the switch on to start the engine. With a cold engine as soon as the oil pressure comes up it should go out. Unless the water temperature SWITCH or the oil Pressuer SWITCH are bad.
f your gauges are showing you normal operating temps and oil pressure then your oil pressue SENDER and water temp SENDER are working corretly.
With the check engine light on the motor will be running in what they call SLOW mode and will nut run above that 2500 to 2600 rpm range to prevent engine damage.

After the CEL is fixed then follow JQs suggestions above.

Here is a link to what to look for over on CCF

LINK

[Rusty Barras]

run a code scan on the ECU... If the check engine light is on, it's storing a trouble code. From there it'll be easier to narrow down. I'm always suspicious of a vacuum leak since it's map sensor based

Procedure
https://www.therangerstation.com/tec...ipped-engines/

Scan tool
https://www.amazon.com/INNOVA-3145-F...64198620&psc=1

[srock]

Install new fuel filters first.

[CheeseSteak1]

Installed new fuel filter and checked the fuel pressure 2 days ago. Filter was a dirty and fuel pressure was in the normal range. I’m going to look into the oil pressure and water temp switch today. I just read that those are the 2 reasons a check engine light comes on and puts the boat into slow/limp mode.

[CheeseSteak1]

Fixed! Bad oil pressure switch. I disconnected the temp switch first and the problem still occurred but after disconnecting the oil pressure switch the check engine light turned off and the boat ran great. $60 new oil pressure switch ordered. Just need to watch my oil pressure till I get the new switch installed. Appreciate the help from everyone.

[SilentSeven]

Love it when people post what fixed the problem. Nice!