Mentally preparing myself for the worst. I’ll give another update later this week after the compression tests. I pray to god my head isn’t cracked...

 

Well, if you're like this guy in the video below, you might find a broken spring. Prepare to be without your truck for a bit. Once you know what's wrong, then you can buy your necessary tools for the fix. If you work on the valves, you might as well replace the stem seals. Watch the video and you'll understand. This job looks a whole lot easier than the 4.7L I just did.

 

I appreciate the video! I’m going to need all the info at my disposal

 

#1 - 190 psi. #2 - 185 psi

#3 - 220 psi. #4 - 0 psi

#5 - 209 psi. #6 - 195 psi

#7 - 209 psi. #8 - 190 psi

 

Yeah, something is holding one of the cylinder 4 valves open. Judging by the design of the 5.7, the broken spring scenario is what I'm thinking, so things may not be as bad as you fear. Your compression numbers are decent in the other cylinders. Less than 25% difference between them. If you do go on to replace the spring, you might as well replace them all. Metal fatigue has probably set in and you don't want to be doing the job again. I got my 4.7 springs for roughly 100 bucks online from a dealer. Fingers crossed for you, buddy. Don't run the truck anymore till you find out what's happening.

 

Umm. Post 11 on May 27 ?