engine problem, PLEASE HELP!

My 86 Nissan sentra will not idle. It ran fine when I parked it about a year ago, but when I went to drive it about a month ago I started it up and it wouldn't idle, and the engine would race like crazy. I found if I plugged a vacume line on the passenger side it would quit racing, but it still idled rough and dies. I changed the plugs, wires, cap, rotor, had the carb rebuilt, and replaced all of the vacuum lines. I changed the computer in it, checked all of the connections, and tried a different distributer. The engine is a 1.6 liter. Can somebody PLEASE HELP?

if you've done all that, i suggest taking it to a certified technician before you do anything else to it

How about the idle controller (not sure on the name). It went out on my friend's car and it would just idle erratically, sometimes it would get too low and die, other times it would idle really high.