When going around a corner car dies

the ignition key cylinder comes as a single unit with the ignition lock assembly. if you want to use the same key as before take the entire lock assembly to a lock smith and they would be able to rekey the tumblers to match your old key.

Then its like my drivers door that I had to replace the lock on the inside of door as my tumblers only lasted so long. My daughter got key stuck upside down and it ruined the lock. Hey, replace lock and use new key for that door or have lock smith rekey it for the old key.

I would take the vin# to the dealership parts counter and show ownership to the vehicle and have them make you new keys might cost $50 or so

yes! sound like the anti-thief system is causing all the troubles. the ignition lock cylinder has two small wire that read the chip on the key and send signal to the computer when you insert the key to the lock cylinder. because it ( the wire ) moves every time you turn the key, after a while the wires will break and cause an open in that circuit.
you need to replace the ignition lock cylinder ( you can repair the wires, but I donot recomment.)
you can either have a lock smith to rekey the lock cylinder to your original key, or you can just take the new key came with the lock then have the lock smith make a copy of the new key with a chip has the same resistor with the old one.

well if you can get the key in and out but cant turn i would first spray some lube into the tumblers but you have to make sure to get the stuff from the parts store thats for that second is this an automatic on the floor shift if it is it could be shift linkage other thing would be to call a lock smith to come and reset or rekey the lock and if the steering wheel wont lock its usally becuase the tumblers in the lcok are miss aligned or stuck or broken etc...

unless your explorer was keyed alike (was requested that 1 key fits all) the only way to address this issue is to 1 try using liquid graphite (lock oil) in the locks 2 have a lock smith look at it and correct the problem or 3 (if you are handy) take the locks out and have the door locks rekeyed to to a new code, or rekeyed to work with your original key.
If you had bought this car used alot of time dealers will buy cars at auction that where repoed and the cars locks where rekeyed to work

to remove ignition push pin under cylinder as you turn it there is a pin if you remove the columb caping off it will be quite visable

average charge is 35.00 from lock smith
if you take old cyl and old key to smith they can re key a new cyl for arround 50 -75 bucks

the main relay has nothing to do with that.. that would be a starting issue.... it sounds like the mechincal side of the ignition is going bad... i've seen it a bunch of times. it might need a new key cylinder usally that will need a lock smith... but your local dealer can rekey it aswell. but i'm about 95 percent that it's a mechnical ignition issue!