Had to adjust my idle - why?

[PKRWUD]

I just wrote this in another thread:

At the TPS:

Either by back probing the connector, or by piercing the wires with a small safety pin, attach a DMM pos lead to the green wire, and the neg lead to the black wire. Turn key on, but do not start the engine. At closed throttle, the DMM (set to VDC 10 scale) should read below 1 vdc. Rotate the throttle to WOT, slowly, and see that the voltage increases smoothly. At WOT, it must be more than 4.5vdc. To adjust the setting, loosen the two bolts that secure the TPS, and try moving it. The optimum setting at idle is .95 vdc. If your reading is way off, and you cant move the TPS enough to get within range, remove the TPS and try elongating the holes with a rat-tail file.

After resetting the TPS, disconnect the negative battery cable for ten minutes. While the cable is disconnected, turn on the headlight switch to drain any capacitors. Turn the switch off just before reconnecting the battery cable. Start the engine, and let it idle for 1 minute. Then, raise it to 2000 rpms for 1 minute. Shut off for ten seconds. Restart, and turn on every load you can (a/c with the fan set to high, high beam headlights, etc.), and let it idle for 1 minute. Then, with the loads still on, raise it to 2000 rpms for 1 minute. Shut off all loads, and shut off engine. Wait ten seconds. Restart, and go for a 10 minute test drive. Drive fairly aggressively. Shut off engine. Restart after 10 seconds, and check the idle.

Take care,
-Chris