2750 RPM Limp Mode

[roeboat]

I got a 2005 Response LXI with a Monsoon 340 and as we were cruising Torch Lake the engine cut fuel and limited the RPM to 2750. All the gauges read normal and the engine itself felt normal temperature too. If I slowed to about 2500 RPM for a couple minutes it would allow me to accelerate above 2750. Everything feels normal until it cuts fuel. I've never had this problem until today and it happened about 5 times. I don't know if it has something to do with going 30 for half an hour at a time. We've never been on a lake this big before. Anyone know what causes this?

[formulaben]

Was there any beeping when this happened?  My understanding is limp mode is triggered by high water temp, low oil pressure, or high transmission temp.  If there's nothing wrong but the ECM is commanding limp mode, then one of these 3 sensors could be bad and sending false signals to the ECM.  Both the oil pressure and water temp gauges on your dash are independent of the sensors that go to the ECM, so keep that in mind. 

Alternatively, if you're seeing good oil pressure and normal water temps, then maybe it is an actual transmission overheat condition.  I'd check your transmission fluid as per the link below, as it's not as straightforward as you'd think.

[electricjohn]

If your not getting any alarms, the ECM may think your engine has not warmed up, there by limiting RPM's. A faulty (unlikely) ECT sensor would cause that.  Fuel pressure would be my guess though.

[roeboat]

I wasn't getting any alarms and it runs great then instantly cuts fuel so the boat won't go over 2750. I'm going to check the transmission today. Would a faulty ECM sensor sound an alarm?

[justgary]

2 hours ago, roeboat said:

I wasn't getting any alarms and it runs great then instantly cuts fuel so the boat won't go over 2750. I'm going to check the transmission today. Would a faulty ECM sensor sound an alarm?

 

16 hours ago, electricjohn said:

Fuel pressure would be my guess though.

Honestly, check the fuel pressure like @electricjohn said.  You should have a constant ~42-44 PSI at key on, idle, and WOT.

[electricjohn]

4 hours ago, roeboat said:

I wasn't getting any alarms and it runs great then instantly cuts fuel so the boat won't go over 2750. I'm going to check the transmission today. Would a faulty ECM sensor sound an alarm?

Yes, but that is limited to the  ECT, TPS, MAP, Knock and ICM. If there are ECM problems in itself, code 51 and 81.