Well, I just spent $160 to have the sparkplugs and sparkplug wires changed and the mechanic was as disappointed as I was. It STILL idles rough when either put in gear or sitting at a light. I actually have to put it in neutral because of the rough idle and vibration. It never stalls, but run rough and seems to just vibrate bad. The mechanic tried cleaning the IAC I believe it was, and still no change. I just now unplugged it (I think it was the correct plug) and it made no difference in the engine idle speed. Could that be the problem? I need a new one? What does the IAC look like in a 93 Ranger? Want to make sure I am talking about the right part. It is fine under neutral, but when put in gear, does a "uh -uh- uh" type idle. Seems to vibrate the whole truck. Going from drive to reverse seems to be the worse for the "almost stall" but never does. Have a very slight leak of transmission fluid too, not sure if that matters or not.