I have a Beech Sierra with a Lycoming IO360 engine - have been flying it for
years.  In the last month or two, I've noticed the peak EGT (one probe only)
has come down almost 100 degrees.

I've also noticed that I can lean to LOP and the engine runs reasonably
smoothly, while the last time I tried this a couple of years ago, the engine
would run very rough at LOP in cruise.  I normally operate the engine at
about 65% power (22 inches of MAP) requiring 8 to 9 GPH to get ~50 degrees
ROP.

Anyone have a clue about what I might look for that caused the change?
Anyone else able to run LOP with one of these engines?  Would I reap the
same benefits as with the TSIO 550 running LOP?

Regards,

John Barrett, CEO
Leading Edge Composites
PO Box 428
Port Hadlock, WA 98339
www.carbinge.com