EGT is used to keep the mixture at a safe temp. What I mean is, if the A/F gauge says your running at a good percentage but your temps are to high. Then you need to get them down even if it means adding more fuel and running slightly rich.
Fuel can be burn early for several different reasons. Your cylinder temps are to high and your spark plug is getting to hot and igniting the fuel all by itself. You may need to go to a colder plug setting. Deposits built up on the pistons and valve train can cause detonation. Any sharp edges on the piston valve seats or head. Having your timing advanced to much. Running to much boost and leaning out the mixture. Bad gas. A really hot day when running the same amount of boost you would on a cold day. The list goes on but I'm sure you get the hint.
GET A KNOCK SENSOR
WD
