So I bought a 02 Limited, 3.7L 4x4 with bad rod-knock in November and just got the motor installed after a complete rebuild. It started just fine and I drove it around town, 4 or 5 times, probably 20 miles total with no real issues other than discovering the speedometer doesn't work. I was messing around with the speed sensor and associated wiring on the rear axle yesterday and then we had a foot of snow last night after being bone dry and super cold for about a month. Went to start it this morning to do a test of the 4x4 system in the snow and the battery was super weak and could barely turn it over. I tried cranking it several times (don't remember how many) till the battery was spent. Hooked up the battery charger for a couple of hours and then tried to start it again - battery was strong and it started up just fine, and then died after about a second. Tried again and again and again with exactly the same result - would fire up fine then immediately die. My gut tells me it's a key/security issue associated with the low battery and multiple start attempts when the battery was low. Does that sound reasonable? Is there a way I can reset the security system so that I can start from scratch? Or do I have a cam or crank angle sensor issue? Something else? Any suggestions where I start trying to figure this out?