quick question

Hey guys would a cracked manifold set off my check Engine light or bad plug wires maybe?

cracked manifold could cause the o2 to read incorrectly, and bad pulg wires would cause the engine to miss.......so yes.

do the key trick and see what codes it throws.

whats the key trick? Im intrigued.

Chrysler Engine Controllers will blink out the fault codes on the "CHECK ENGINE LIGHT" (CEL). To get it to blink, you have to turn the ignition key to ON-OFF-ON-OFF-ON within 5 seconds. By ON, I mean ignition on, NOT start, i.e. don't start the motor.

You have to have a Chrysler engine controller to do this, and NOT all Chrysler ECU's did this.

I think the most of the 90's XJ's do this.