engine surging with a/c on when hot

[97Pathfunder]

Hey guys little help here!
I have a 97 that when i have the a/c on when it gets really hot, the engine begind to surge from 500rpm to 1000rpm, and it will overheat if its hot enough.

any ideas?

[azaizai]

I forget, do those have E-fans or belt/crank driven ones?

Either way, make sure they're kicking on/increasing flow when you turn on the AC. The condenser in front of the radiator tends to get hot with the compressor running, so extra airflow is important.