temp not holding

[dgprop]

just changed my extruder head for a new one, the temp now varies between 15deg either side of the set temp.
any ideas, please

[asusdk]

Anytime if you change the Cooling, the Hotend, the Heater or anything that can impact the Temperature, you should run an PID-Autotune

M303 C10 E0 S210 U1 // Hotend - 10 Cycles to 210 Degrees

Greets
AsusDK