Not saying this is the problem but just a thought. If you are going uphill your engine needs to work harder/needs more fuel to propel the vehicle forward. If you have a weak spot in your fuel system you could be leaning out. If pump wasn't able to suck up the fuel it would be burning out since fuel flowing through it acts as a coolant. While I don't believe this is your case. So from that point you have your fuel filter, fuel pressure regulator, and fuel injectors. All potential weak spots when leaning out. Again, pull your plugs and check the color of the deposits on them to see if there are any differences in color between the 4. Color can be an indicator as to what is or is not happening in your combustion chamber.
Someone mentioned crank posistion sensor. I've experienced that once. I wasn't able to start my car at times. The sensor wasn't picking up any signals therefore my ingintion system would not fire. It was random for a very short time and then my car just wouldn't start at all. Replaced and Kosher.
Then vacume leak...that's possible too. __________________  |