So normally I wouldn't give a flying rat's ass about my AC on my 4runner, but I have to start picking up my little sisters from school soon and having AC in the 4runner would be nice. Today I went out to my 4runner (1989 3.0) and tried turning on the AC to see if even worked. I've never messed with the switch and found that when I turned on the AC the idle went wayy down almost killing the engine at idle. Is there an adjustment for this anywhere?

Also I know the original system had R12 in it and I was just going to throw in some R134, yea I know probably not the best thing or proper thing to do, but I did it on my 84 model and it works fine and the AC works. It just leaks out over time and I have to put a small can of the stuff in it once a year. Was planning on doing the same for the 4runner. Anyone know which side is the high pressure and low pressure port? Both sides have shrader valves and I dont want to use the wrong port.