Code P0300 Random Misfires

[syclonegs2003]

I finally found the problem.. After removing the rear valve cover and bumping the engine over, the #4 intake valve is not moving or opening. Removed the 1.9 Rocker and found the push rod (rocker end) tip broken off shortening the push rod. I found the broken push rod end tip in the head near #4 rocker stand. I also pressed down on the rocker arm against the worn push rod and bumped the engine over and the push rod/rocker moved up and down indicating no issue with the lifter or cam lobe. Also noticed wear on all the other push rod rocker end tips. I installed these 1.9 Rockers 17 years ago in 2007. I will change all push rods and verify #4 intake valve opening/closing before buttoning it up.

Question, can I reuse the rocker arms bolts?

[harofreak00]

I'm not sure how you got 150psi compression on a non-operating intake valve.

The stock rocker bolts are TTY and are NOT reusable. INTENSE sells reusable rocker bolts

[syclonegs2003]

I am not sure either about how the compression on #4 cylinder was 150 psi but it was, I rechecked it 3 times . All the cylinders were very close to being the same within a couple of psi..I ordered a new set of rocker arm bolts from ZZPerformance. I could not find them locally. The 1.9 Rockers had approximately 140000 miles on them and the push rods were originals with 183000 miles on them at the time of this failure. All the other push rods show rocker end tip wear and I have been hearing valve train noise for about a year or so. I already have new Melling (605) push rods and am waiting on the new rocker arm bolts.

[syclonegs2003]

Received the TTY Rocker bolts and installed and Put all back together and started car...sounds and runs great, no valve train noise, no misses, no codes etc...Only one issue was a coolant leak on the lower elbow on the Alternator/tensioner bracket probably done while I loosened it wiggling it to remove and reinstall the rear valve cover..I replaced both aluminum elbows this morning and bled the air out of the cooling system...

[Captain Ali]

I'm having these exact same symptoms with my 2002 SE.

[Captain Ali]

Have you tried tightening down on the three bolts that hold the passenger side fuse panel in the engine compartment ? I'm doing that next.