Just wondering if there was a way to get rid of the interference with the screen and speakers while using a power inverter and playing PS2 on the avic-d3

Yes. Buy a better power inverter. Inexpensive ones will cause all kinds of electrical noise.

Or (maybe) you could put noise isolators on the AV inputs, but those tend to lower the strength of the signal anyway.

Alrighty...i'll give those a try, thank you

As the others said, a better inverter will improve it.