You are doing the run-up...What does it mean if you pull the carb heat, and the rpm's increase?
1) You forgot to push the mixture in to best power before advancing the throttle. You were still leaned from taxiing to the runup area. You also probably weren't leaned enough since proper agressive leaning would have made your engine stumble when you advanced the throttle, or
2) Your mixture cable broke during taxi, or
3) Your carburetor isn't running rich enough - an adjustment screw worked loose, or
4) You had carb ice form during taxi (common with a 182 O470), and you didn't notice the stumble when the ice/water was ingested; the carb heat cleared the ice and now you can make more power, or
5) There is an obstruction to the filtered air intake. Maybe it was frozen over... but then you would have noticed that during your preflight, right?
Here's another "fun" one, Why is it called a 4096 transponder? The DE I know used this one just as a FIY.
The transponder uses an octal (base eight) numbering system. Each digit is 0-7, for a total of 8 possibilities. 8^4 = 4096.