Sounds to me like you have a BAD Ignition Switch. Also you might have the Battery "Load" checked to eliminate it as a problem. When it ran, did it charge itself? I.e. the Altenator is working and throwing atleast 14.1 volts at 75 amps minimum? The funny smell could be overheating contacts in a switch or solenoid. Is the smell on the inside of the cab or under the hood? If in the cab, it's definately the ignition switch, if under the hood, check the starter solenoid and starter relays.

 

I'd say under the hood. I don't have to pop the hood to detect it, but I usually can't smell it in the cab.

UPDATE: had it dropped at the local shop-it started right up for them. They're keeping it for a few days for observation.[>:]

 

get a bottle of heat

 

fuel pump may be working but not able to get enough pressure to run every time. My vote goes to fuel pump.