The CAT probe is located before the throttle valve in the R22 carburettor. The throttle position therefor shouldn't affect indicated temperature much (hence the need for the "below 18in apply carb heat" placard).
It can imagine that you would see a slight decrease in indicated CAT because more fuel is being injected at higher power.
Last edited by lelebebbel; 15th September 2012 at 23:11.