#2 & 3:
The load is a vehicle damper. The driver to create the PWM is ATiny85. The shunt voltage is measured on a scope 75mV for a 3A current. The PWM is being controlled using a 10 turn, 10K potentiometer. There isn't a specific region where the 150mA fluctuation is occuring. It appears across the 0-3A scale quite randomly. I've looked at the PWM signal and it is rock steady. I'm unsure if it's the MOSFET causing this or if I could add something to the circuit to improve it?