poorboy99

at work i have a 2004 truck with 6.0L that has p0300 code flashing, we did plugs, wire and injectors on cylinders 1 and 8(the 2 that were continus missfires). did not help so we did a compression test and found all but #1 at 120 psi and #1 at 30 psi. what could be the possible cause of this? hole in piston, bad valves? took valve cover off and rockers are ok and tight. any ideas as to what is causing this would be very helpful, thanks in advance for your replys.


jason