'04 Cadillac deville will start but wont run?

Should not touch the gas pedal on fuel injected car so sounds like you have to compensate for fuel coming out of injectors at start up because the injectors are maybe a bit clogged. Try injector cleaner and take it for a nice high rev. run. If you want to stay on the right side of the law then try a run in second gear at 70 mph, or have some fun it see how it'll fly. If this doesn't clear up the problem then you are looking at some shop time, oh and don't forget to check air filter,PCV,fuel filter,etc. - basic stuff.