i'm gonna have to agree. sounds like the timing is wrong.
someone posted the FSM pages here -
KA24DE Timing - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum
you can open it up and see if the timing is right.
A) see if the lobes are pointed the right directions at the right time.
B) manually turn the engine over until the timing marks line up. They only line up one way.
(as seen here -
http://i63.photobucket.com/albums/h1...re021Small.jpg) It can take a while to spin and spin and spin the engine over to get them to line up, but it might be worth the time and effort if you don't want to just tear it all apart and re do the timing.
in the vid, you can hear some popping in the intake, which supports the timing being wrong. The revving part is strange. Could be something stupid, like the timing is wrong, it backfires into the intake, that hot air tweaks with the MAF and that makes the ECU think it needs to dump more fuel.
You said it doesn't do that if the MAF is off?
Have you gone over the whole thing to check for vacuum leaks? every gasket is good? every line is good?
You are 100% sure the throttle body closes as it is supposed to, right?
Have you looked at the idle air control valve yet? Is it stuck open or something dumb like that? I'm assuming it won't even idle at all if it is unplugged, right?
Have you ruled out the possibility of the problem being spark related? (not spark timing, but the spark itself)
It almost sounds like you have a few things wrong with the engine and it is causing that problem.