Cadillac Repair: bogging down, fuel pressure gage, gas caps

Question
my 1999 escalade won't take gas sometimes. if i wait in it with engine running.it start it won't take gas .you can mash the petal all you want.if you get wrong gas it does this.no passing cars. won't pull at all just sometimes.what up with old gas caps or if new. if you don't put it on right the engine check light comes.then put in on again it goes off. please help a lady, i only worked on 1963 to 1994 models. thanks confused.

Answer
You need to check with a gae to see what your fuel pressure is at. I like to use a long hose on my fuel pressure gage so I can tape it to the outside of the windshield as I drive down the highway so I can see what the pressure is doing under hard acceleration and when there is a load on the enginme as if climbing a steep hill.