My 2005 EB V8 Explorer has suddenly begun to jerk and buck when pulling a light RV. Also it suddenly acts like it is going to lose power when I am tooling down the road. There is no pattern, speed or condition that seems to cause the bucking. I've had the main throttle sensor replaced and the alternator replaced. I am running out of money and patience. Please help.

This rig is fuel pump shut off sw located on the passenger side just under carpet on firewall poke the red button on top of sw if it clicks it was activated heavy bumps pot holes or even a careless passenger kicking it will trip it too. If not check fuel pressure 32psi minimum at idle bring rpm to 2500 if the pressure fluctuates below pump/filter may be the cause. These trucks are also very sensitive on fuel mixture check engine light may steer you closer to target just be aware that a low fuel pressure condition can cause false codes,oxygen sensor ect.

Check to make sure you are not in overdrive when pulling the load. Not certain what setup you have, but it sounds like the vehicle is trying to find the correct gear, maybe.

Just to mention it, as I'm sure you already checked; make sure the small RV you are towing does not exceed the weight for the vehicle and equipment.

Sounds like it could be a misfire. how many miles are on the vehicle?