Please help my 2003 4.7 cherokee overheated and shut down, compression check showed 140 psi on all cylinders but #4 90 psi, i pulled oil sample no metal, no coolant in oil, by the way no check engine light active or inactive, pulled valve cover, #4 exhaust rocker lying in head, no damage to rocker or cam,exhaust spring all good no real signs of damage, im stuck on what to do next, i can put the rocker back in and out , please help, Thank you, Nathan