I have a 2004 nissan titan with 92,000 miles- i was on the highway and the truck shut down on me-- all the lights on dash were flickering, i pulled over turned the truck off and then started it and it started right back up again like it never happened.. it did it again last night but this time it didn't start up-- until this morning--- what could be the problem?

When mine did this,I took both cables off the battery,for 3minutes.Make sure you are in Park,jiggle the lever.How about the service engine light is it on?

Most likely a wheel speed sensor starting to go bad, possably a wiring or Modual Issue.

You would have to pull the code with the light lit to tell you were to start the Diagnosis.

Need to know what the light looks like or what it says.

check all fuses in dash and under the hood

If I got $ 800.00 every time I replaced spark plugs and plug wires I would be living on a tropical island !
The almost stalling may not even be about spark plugs, which by the way are about $6.50 at any auto parts store.
I would think you should have a check engine light coming on in the dash, or at least have someone plug a scan tool in to retrieve any codes.
Find a reliable auto center, and have them take a look.
Please let me know what you find.

As far as your 4WD light problems, can't help you. The loose hose sounds like the front diff vent hose.

chances are that the cable broke, youll have to open the hood from under the car, and then replace the hood release cable.

sounds like the switch

Try checking your battery and or starter. If not them you might have another electrical problem.

Yes and this easy to do. Just drain at bottom fill at top.