'94 3.0 4runner 114K runs very rich and rough with a/c on and smokes ALOT (white/tan so thick you can't see cars behind you)! Turn a/c off and within 1 mile it's back to normal, no smoke, idles and accelerates smooth. Oil/coolant level stay full and clean. Changed oil and thought I smelled fuel in it.
Any thoughts?

 

Never heard of anything like that before, try checking the vacuum lines, there are vacuum lines that idle the engine up a little when the a/c is on, make sure everything is hooked up properly, thats about all i can think of.

 

Now that is quite the phenomenon...I agree with myyota, check some vac lines. Almost sounds like a vac line or better yet a valve or sensor of sorts is leaking coolant into the engine when you turn it on.

 

...wait, you said '94 right? and it's a red 4runner?? OMG You got the special edition SMOKE SCREEN??!!1!




or yeah, what myyota said, check the vac lines, and just for fun, check the A/C switch wiring, maybe something's shorting out against something else?...because as far as I know, the AC has nothing to do with fuel/air ratio, but it will idle up the motor when you're sitting at a stoplight...

 

Sounds like switch vacuum lines.