Hi Customer, my name is Ed. Welcome to Just Answer!.
You guessed right! Fuel tank venting is a little lower on the 07 models than what's practical for anything that goes off road or gets somewhat submerged. The vent tube connects to the inner left frame rail at about the location of the driver's door handle area and then runs back over the top of the tank. Look for the 1/2" ID hose that seems to dead-end at the frame rail and that would be it.
I'm expecting that water is the actual cause for your suffering though. Mud is mostly excluded from this vent system, but there is nothing to prevent water from backing up the vent tube to your vapor canister... flooding it... and blocking tank vent flow. Lowering the tank to remove and replace the vapor canister will be required. Even though the canister might some day dry out, the effects of dirty water entry won't disappear.
This situation probably calls for replacement of the ESIM (evaporative system integrity monitor), which may or may not come with the vapor canister. Its job is to monitor the evaporative system for leaks, with the vapor canister storing fuel vapors that occur during normal operation and during fuel fill operations. The ESIM likely got a snootfull of water and crud, so it's a gonner... the reason your CHECK ENGINE lamp is on is quite likely from failure of the ESIM.
I've seen instances of lift-throttle stalling and related evap system failure codes set from water being drawn out of the canister to the purge solenoid underhood, which can then stick open. Your purge solenoid and purge lines need to be inspected for water aspiration and for proper sealing of the solenoid when de-energized.
Aside from the time and expense of replacing the canister-ESIM assembly and the purge lines/ hoses, the repair is fairly simple. Clear your PCM memory after repairs by performing a 30-second battery
disconnect and you should be all good.