I have a 2003 Z06, 140k miles with no previous issues. While moderately driving I suddenly lost significant power, feeling like I lost at least two cylinders. I limped 5 more mile to home.
No unusual noises excepts what sounded like compression bursts from passenger side somewhere. Scan showed multiple misfire codes. Fuel check good, spark good, plugs good. It got interesting with compression check.
#1, 2. 4 and 8 only had 25-35psi and the rest had non. on second round little to no compression on any. On third round #1,2,4 and 8 again had very low reading. Timing chain has considerable slack but no jump and marks are fairly aligned. Crank feels really hard to turn by hand at points, enough that I was forced to bump the starter to continue. Any opinions where to look next? Would excessive slack in the timing chain cause timing to be off that bad?

 

Excessive slack in the timing chain could have bent valves, if thats all the compression you have, you have serious problems

 

So, pulling the heads would be your next move?

 

Are you spinning it by hand when measuring compression?

 

Can you tell me just how much slack or deflection in the timing chain can be tolerated before potential damage to valves and pistons?

 

No,,,(LMAO) !!! I checked compression after I verified fuel and spark. Pulled valve covers and visually looked for damage or non moving tappets or push rods then, got into the front cover to inspect timing chain.

 

It just feels like timing, was the root cause. I guess the only way to find out for sure is to pull the heads and look for damage. I'm trying not to head off in the wrong direction if someone here with more experience than I have, knows better.

 

Just making sure.