How come my junk idles when i reset the comp?

I would like to know this: when i reset my computer on my 95' mustang gt, how come for about 2 days afterward, shell idle like a beast, lope and all....sweet sound....like a racecar.....then suddenly everything goes downhill after, the next days in a row the idle gets progressivly(SP!) worse and worse. It will seem like its gonna die at stops, then eventually it WILL! now it runs all choppy like it did before i had my whole ignition switch ficiasco...help? is there any way i can teach my computer not to learn(how?) thanks

i hear ya man....but how come when it knows nothing it idles great, and when its suposta learn it gets stupid? is my computer retarted? can i disipline it so it wont try and learn?