I drove around for about 2 hours yesterday getting stuff done for the new job (drug test, paperwork, etc). Here in New England it was raining and snowing all day. The Durango took it like a champ but today as I was going to leave for work, the car didn't want to stay idle. The car did this once before so I figured it was a IAC valve going south. This time, the car won't stay idle until I give it gas and kept the engine revving above 2,000 RPM for a minute. After that it will idle normally. For some reason brakes are affected as well. I barely get on the brake and the tires lock up. Once the engine gets warm (about 170* F), it would run normally. It did this leaving for work, and leaving work to run errands for the store.

To be honest, I think the truck hydrolocked the day before. A few puddles of standing water came up out of nowhere on the highway yesterday, and I'm afraid some water got in via the homebrew intake because after I plowed through the water the car started sputtering so I pulled over the side of the road and the car stalled out. Cranked it a couple times, didn't start, but after a few minutes of fiddling around, the car started and I finished my errands. Can't help but think that water got in the engine and screwed something up....like head gaskets and the reason why the car won't stay idle is loss of compression due to damaged head gaskets...

 

It's highly unlikely that your engine got damaged from water splashing up from puddles, and you'd know if it got hydrolocked, it would have made bad sounds and stopped immediately. It's entirely possible that water is shorting something out that's causing issues.

I'd be suspicious of the battery and/or battery connections for the stalling and poor running.

 

The puddles I hit were on the passenger side and the battery is on the driver's side. The worst puddle caused break waves that hit over the hood and into my windhshield. Any electrical components located underneath that could have caused this?

 

The PCM is on the inside of the fender on the passenger's side right next to the airbox. The battery and connections still could have been causing issues before hand that got aggravated by the water, besides cleaning the battery terminals is dead easy.