It's an AFM (Air flow meter) problem (wire, ground or AFM)!
pretty sure. Borrow one and do a test.

OR basic stuff: fuel & air!

Check this sucker: http://www3.sympatico.ca/huotx/engine/throttle_body1.jpg
is the switch working? Wire good?

Unplug IS (idle stab), see!

Check fuel pressure, see!

Tripple check grounds, see!

FPR (Fuel pressure regulator), borrow one and see.

ECU connection or ECU.

Fuel= clean? clog tank? clog/bent return fuel line.

If not, take a hammer and bang the hell out of this engine (he he).

I don't know what i am talking about, just some suggestion, that's all.
Ben