The other day, after we landed to refuel, we taxi back to the runway and we did the run up of the engine, everything was running perfectly, with the normal RPM drop and no difference between L and R mag, both with in parameters. After completing the check list and entering the runway we add full power and started our take off roll with all parameters correct, after rotation on our first climb sector, we notice that the EGT on cylinder 1 had a difference on 200 to 300 deg Fahrenheit compare to the rest of the cylinders. with this in mind we decided not to leave the airport and return to land (engine was running smoothly). After landing we did another Mag check and we saw that when turning the kay to the left mag, engine was running rough and the EGT went all the way down, After checking with the mechanic, and testing the spark plugs, we realized that the spark plug was dead.

EGTs are normally used operate your engine at required power settings on different density altitudes, but also can tell you a lot more.

So always keep an eye on the EGTs they provide a lot of information about your engine.