Parking down hill led to rough idle, no power

The other day I parked my 96xj down a pretty steep hill on a scouting trip out wheeling. The jeep fired up but would not run for squat. No power and wouldn't rev over 2500rpm. I slid into neutral and still wouldn't rev. I coasted down to a flatter part of the mountain and turned off the jeep. Waited 30sec and fired it back up. Ran like normal. Odd as with the fuel injection I wouldn't have thought that parking or driving on an angle would have caused for loss of power.

thoughts?

thanks DT

How full was the gas tank?

Sucking not enough fuel, with too much air = issues.

I figure that I had only burned off 3 gallons of a full tank, based on my average mileage and the miles to the point this took place.

I've parked in the same spot with my 1994 YJ without any issue so it seems odd that my 96 XJ would give me fits? Are the gas tanks and pickups that different?