Mitsubishi Repair Problems? Ask a Mechanic for Answers ASAP
This is a pretty good indication of a possible pump issue, specifically the check valve in the pump module may be failing allowing the fuel to run backward when the pressure (gravity based) is increased.
I take it you have consistently been able to reproduce the hard starting when parked on an incline, and do not normally see it in any other parking scenario?
It looks like we missed each other.
As long as you are able to consistently reproduce the hard starting by parking on an incline and not in any other scenario currently, and you aren't seeing any other symptoms (like slow cranking) at the same time, I would say it is likely the check valve inside the fuel pump letting the pressure bleed back.
As long as it remains in this state where it only occurs on inclines, I would not put too much thought into it just yet, it should not be any urgent matter etc. If the problem persists at level surfaces then further action would be warranted.... at that point apart from your basic checks (making sure something else is not failing affecting the fuel pump, like the crank sensor etc) then you would want to pull the fuel rail and pressurize the system and make sure there are no leaks from the injectors into the engine as it sits for an extended period... if there is then that would need to be addressed of course, if there is not then a fuel pump would be your likely culprit.
Again until this worsens beyond just an issue on inclines I would not be too concerned about addressing it yet; this is not uncommon behavior on many vehicles even when new if they are parked at certain amounts of incline over night etc.