Jhooper's posts about power loss reminded me of an incident I had about a month or so ago.
I was flying a Cessna 182P with a Continental IO-470 (yeah, IO-470). I had a really hot pax (temperature wise ), and, being a blistering hot day, climbed up to 9,500' to get her some cold air. It was a normal climb all the way, and I leaned the engine as recommended--50 degrees rich of peak EGT, cowl flaps up, EGT's on all cylinders steadily around 1370 and stable CHT's, OAT of 43 degrees F and I think the oil temp was around 170. Fuel flow was 13gph. I was using 2400 RPM on the prop, and I think I had something on the order of 22" MP...standard cruise settings for the engine. I have used it all the time, engine's made it through an overhaul and 2 annuals with me as the primary pilot with no major problems.
All of a sudden after being in cruise for about 15 minutes, I noticed the fuel flow gauge start to fluctuate wildly...back and forth from about 18gph down to about 4 or 5. I could percieve no engine roughness, nor did I notice any appreciable EGT/CHT change. Manifold pressure and prop RPM were steady, as were oil temperature and pressure. I immediately prepared for engine failure (of course thankfully I had altitude and an airport with 6,000' runway right below me) and then began tinkering with the mixture and throttle. Nothing I did seemed to change it much, but after about thirty seconds had passed everything returned to normal for some odd reason. I wrote a note when I landed to my A&P but unfortunately I had to leave town the next day and haven't been back to hear an explanation. From what I've heard, the airplane's been flown since over a long distance and is running fine, but I still haven't talked to the mechanic.
Here's the airplane (and hey...that's me!) Pardon the weird expression...I was looking directly into the sun
Photo © Jonathan Derden - SPOT THIS!