first scan for codes, and fix the codes directly.
2nd, if all else fails, I have fixed weird "no code" problems in my 04 grand cherokee by disconnecting the battery and cleaning it, double checking my grounds, disconnecting the ecu cables 1 by one (really important to have battery disconnected) and removing fuses and relays 1 by one and cleaning all the contacts with a pencil eraser.
sounds stupid but it's worked for me. a lot of the electrical problems I've faced have been really simple things that cause a lot of weird gremlins
also, I am not sure how the fuel system works on an 05, but on my 04 I was having fuel pump issues where some mornings my jeep would turn on fine, and other mornings it would crank but not want to start until I tried a few times. Turns out the fuel filter has a fuel pressure regulator in it that had gone bad and it NEEDED an official mopar dealer replacement part because an aftermarket part only made it worse.
