TSB help bad valve guides
 

My friends 2007 Panel started missing on #3 cylinder. His mechanic did a compression check to find #3 cylinder at 110 psi and the other cylinders at #180 psi. The mech already has another ladies HHR apart with bad valve guides. My buddies engine has 55,000 miles and he's original owner.

Is there a TSB or notice addressing this issue?
Thanks

How does the wrench know it's valve guides ?

Need to do a "Leak-Down" test to confirm this.

Or as Old timers did, add a teaspoonful of oil in that cyl & re-check comp. If its about the same, then it's top end.

Had the same problem with my '07. I' see if I can attach the post on it.

https://www.chevyhhr.net/forums/problems-service-repairs-42/code-po303-37708/

Follow up. My buddy's mechanic pulled the head off his 2.2 to find heavy carbon deposits on all the exhaust valves and loose valve guides as well. I'm surprised to hear of this situation on a engine with 55,000 miles. His driving is primarily in town at under 50 mph speeds, maybe this is the major contributor.