Dead Battery from Keys in Ignition for 24 hours in Start mode

Alternator fault possibly.

Check the battery... sounds like its dead.

The battery dies after sitting for a few hours ? Parasitic drain on the battery ! With the key off all fuse's shouldn't be hot ! Bad ignition switch . Find a wiring diagram at www.bbbind.com an check power at ignition switch . Look on you tube , a lot of videos on basic electrical trouble shooting .

You have a parasitic drain somewhere. We have an almost identical model at work and we have an ignition problem where you can remove the key in accessory position which leaves some of the electronics on and drains the battery. Faulty light switch, interior light left on?

You need to have your fuel pressure checked. fuel filter, etc.

Most likely the alternator is bad. Best way for you to check is start it up, then pull the negative cable off the battery. If it dies the alternator is dead. As far as it draining when parked, I have replace a lot of the ignition lock set and keys because you can put it in the accessory position(All the way back) and pull the key out. Leaving on things like the radio.

In regards to the 1614 code. You should/could also see code 1610.

P1610/P1614
P1610- Ignition key/engine control module (ECM) malfunction
P1614- Immobilizer control module (ATS) coding plug communication-no signal. (ATS=anti theft system)
The ECM is getting a signal form 1614 that the key/ignition is not providing a correct code. Hence, the programing is told to fail engine start. Should the engine failing to start with 1 key, try the other key.
Should the Anti Theft System go into lock mode with one key, try the second key. If that does not unlock it then do this: with either key turn the ignition to ON position for 5 seconds then BACK to OFF position for 5 seconds, the to On position for 5 seconds then back to the OFF position for 5 seconds. If the ignition key is and intergrated key (remote: unlock, lock) the batteries should be changed in both keys. Low battery or dead battery provides low or no security code signals to ECM -- hence incorrect or no signal.
When replacing the batteries: be sitting in the drivers seat with the 2 keys within 24 inches of each other. And make the battery change within 1 minute for each key and within 4 minutes of the first key.
If that does not work,Check you users manual for the ignition key sequence on/off series to relearn the on board car computer to the keys.

u must put a key to ignition and open a drive door 3 times and press and hold lock button

If the battery is dead, the ignition keys will not release from the ignition. If there is no signal from the transmission shifter that it's in park since the battery is dead, then the ignition lock will not release the keys.  After charging the battery or jumping the blazer to start it and the key's still will not release, try this. 
There is a "plunger" as part if the ignition. Under the steering wheel there is a small removable cap that you can take off and put a small screw driver up into and press the plunger in and it will release the key. Good luck and hope this helps, Keep me posted be glad to help. 

If I understand you correctly your saying that the engine will crank on it's own when the key is not in the ignition? If this is the problem you have a warn switch with sloppy connectors that are shorting out between each other. Another remote possibility is a short at the starter solenoid.