2003 escalade starts but wont stay running

Either the alternator is not being energized with the key on, or the main wire from the alternator to the battery/starter is bad.
Have you checked output on the back of the alternator with the engine running ?

Has the airfilter been changed recently? MIght be worth seeing if it's full of dirt and switch for brand new.
If that's not working, try looking at the spark plugs to see if they are dirty or oily. Light grey look to them is normal.
Fuel filter look ok? again, cheap part maybe worth switching for new

Correct fuel pressure? EGR stuck open? IAC dirty/stuck? Throttle blade hanging open preventing IAC from working? Yune up issues?

did it run good before the key switch was replaced? sometimes the switch does not sit all the way in

You will need to have the ignition barrel removed and replaced with a new one.

SOUNDS LIKE TIMMING CHAIN REPLACEMENT NEEDED

You need to establish and check your fuel pressure to make sure it's the same pressure it is whenever your car left the lot

my cadillac escalade esv 2003 ran out of gas when I put gas back in It now it won't start or even turnover

just floor the acceleration twice and then start it

Did you ever find an answer to this? This is happening to me right now