well, your TPS is one of the primary determinators for fuel enrichment. without it, the car will default to FMEM timing (-10 degrees, same as if you pull the SPOUT plug), and attempt to figure out what the TPS is supposed to be at based off the CKP (rpm) and MAF. The EEC can get a basic idea of engine load by looking at how much air is going into the engine versus its RPM corrected for gear.
If you step on the throttle, the computer will see more air going into the engine and the mixture leaning out and the RPM going up, and it will figure out that you're stepping on the throttle, but it won't know how much, so it'll just dump a shit-ton of fuel in there to keep it from leaning out. This, combined with -10 degrees of spark, make for one crappy-ass drivin' car.
If you unplug the IAC, the car will run fine until you let it go to idle. When that happens, the only passage of air into the engine is through the nostrils of the IAC. With the connector off, the nostrils are closed. Very simply, no air = no go.
This is also a very effective method of cutting the engine off from inside the engine compartment. If something goes wrong while you're looking at it, just flip the IAC connector off - it'll die real quick.
Edit: just thought about this. if your ground straps are missing or corroded, the car will also drive like POOOOP. My wife's 95 was misfiring for the longest time and I could never figure out why until I looked at the computer ground wire to the battery. Yup... hanging on by one strand. Replace the wire, car runs like a top! Also a big one to check is the big strap on the passenger side of the intake by the firewall.