Sydney Hoeltzli wrote:

Last night, on a short hop back to home base after an
instrument lesson (read: extended low power ops),
engine shuddered and ran very rough just after level-off
and power reduction.

Wow, this is the first time I've heard an actual first-hand account of
the engine running rough after the initial power reduction.

Good job handling it, Sydney.


Ground ran with brutal leaning afterwards and checked
all chts/egts on both, r and l mag. r mag ran rougher,
with higher EGT on #4 cyl.

Suggestions? Going out to clean plugs and make sure
all 4 cyl have compression this afternoon, what else
to check? I'm hoping for a badly fouled plug, but
would that produce high EGT on 1 mag?

Fouled spark plug, faulty spark plug, bad lead, bad distributor... all
possibilities.

Was there any drop in CHT on cyl. #4? If so, it could be a burned
exhaust valve.

Let's hope it wasn't anything expensive.

-Ryan
CFII-A/MEI/CFI-H