1994 Ford Taurus Weird Idle

Engine Performance problem
1994 Ford Taurus 6 cyl Front Wheel Drive Automatic

When my car is in park or neutral the idle process will almost come to the engine stalling the it will pick up again to the normal idle process then will go into the low end of "this idle" until the engine heats up to normal the idle will start to smooth out every so often in this idle while the engine is warm it will drop idle again. What Ive tried is changing the oil, changing the O2 senser and Ive let the car idle up against a curb supposedly resetting the idle processing. I cannot local the computer hub to plug an analyzing computer into. I thought it was under the dash near the steering column. Is it behind the dash panels? Help is much appreciated thank you.