Cranks but will not fire

I drove the car and filled tank. Drove car back home now it cranks but won't start. It never showed signs of any fuel pump problems. There has been times I go out to start it then nothing would happen. I would pull the positive terminal put it back on then car would fire right up. Then there has been times where I drive the car loses power and dash reads service traction and no power esc. I pull over and undo positive terminal and car fires right back up. I have looked this up on YouTube and several of people have had this same issue but no body says what was wrong or any part they changed. I have changed out relays. One video the guy has same problem and shakes fuse box in trunk where fuel pump relay is but that didn't work for me. I've seen some where they say its anti theft and to turn key for ten minutes and repeat to reset the key but that didn't work. I feel its a electrical issue more than fuel pump went out because I never had any issue with fuel pump but several issues with something electric. I have read up on this car and apparently has several issues with something electric