I have a 2006 Lincoln Navigator (2-wheel drive - rear). When I attempt to pull my boat (2005 SeaRay 240 SunDeck, 6000# includ. trailer) out of the water on an inclined launch ramp, the Navigator will pull it about 10 feet or so, and then sometimes lose power and not move forward. The engine does not stall / shut-off...It just won't accelerate. I tried shutting the AdvanceTrac with Roll-Stability Control off, but this doesn't help. I don't believe that the traction control is the issue, because 1) it isn't happening when tire slippage is occuring, and the brakes don't seem to be applied (as they would be by the traction control feature). In fact, the vehicle starts to roll backward if I don't apply the brakes. After several attempts (sometimes 5-7 attempts) of immediately stopping the vehicle and trying it again, it eventually will stop the shenanigans and successfully move the boat up the ramp. Does anyone know what could be causing this problem?

- I use Premium fuel, which may not be needed, but I don't suspect this is related.
- This issue ONLY occurs when towing the boat up the launch ramp.
- No dashboard lights come on.
- To avoid slippage, I initiate my climb up the launch ramp by pressing the gas slowly as I release the brake. Could this be a factor?

Thank you!
Morgueman (Eric)

 

Could be the fuel pump starting to fail. Pulling the boat up the ramp demands a higher flow of fuel than normally would be called for. If the pump can't deliver, the engine loses power.

 

How much fuel did you have in the truck? are the RPMs getting higher when you throttle down and did you try to put it into 1st gear?

 

I had about half a tank of gas.
The RPMs did not get higher when I throttled down...it just idled.
After failing in "Drive," I shifted it into 1st gear, and I think it had the same power loss issue once and then it worked on my second attempt.

Note: I went back to the same launch ramp today. I left the weight distribution bars on, and put it in first gear. I left the traction control on (by mistake). I had no power loss issue at all. Very weird, and I'm not sure what is the determining factor...Wish I did to be sure it never happens again.

 

How much gas was in it this time? Any chance it could be a TPS?

 

I had a small bit over half a tank...same amount as when i was at this ramp the first time on Wednesday.

What is TPS?

 

Do you have traction control? If you start to get wheel slippage it limits engine speed. I don't have it so I don't know how it works.

 

TPS is Throttle Position Sensor.

The reason you keep getting asked about the fuel level is that fuel pumps act up and fail more if there is less than 1/2 a tank of fuel. The fuel acts as a heat sink for the pump, so when the level is low the pump runs hot and weakens.

 

I actually had the Throttle Body, including the sensor, replaced anout a month ago. The problem with power loss occurred both before and after this repair.