2002 Explorer sport eng. miss, wont idle

2002 explorer sport 4.0 sohc v6 68000 miles. Engine has had routine maint. (oil/filter changes, air cleaner) but no service to fuel sytem or ignition.

this morning on a 30 mile expresway drive across town. everything was fine until last 5 miles or so. I felt a slight miss/stumble in the engine.
I stopped for a while (approx 10 minutes). When i started driving again on the 30 mile return trip the miss/stumble got progresivly worse. It felt like the egine was cutting out. mostly it happens with light throttle pressure.
when i overtake a vehicle or go uphill it mostly smooths out. towards the end of the drive it got really bad. and would stall when i pulled up to a red light.
Last night i cleaned the battery terminals and kinda cleaned up in the engine compartment. I did get water on many of the electrical connections.

I did pull a few of the connectors to check for water but this did not help.
Any ideas

The symptoms described are consistent with a misfire. Since you're at 68k miles, I'd suggest starting by replacing the spark plugs and spark plug wires. Several folks here have had poor experiences with non-OEM style spark plugs (although I've personally had very good luck with Iridium plugs). You'll also want to go with a better grade of plug wires rather than the least expensive set. The build quality of the low end spark plug wires often will lead to pre-mature misfiring.

If that doesn't fix the issue, then I'd suggest pulling the MAF sensor and carefully cleaning the sensor elements as well as removing the intake air tube from the throttle body and cleaning the backside of the throttle plate.

-Rod