nissan 90 stanza wont idle or drive

[Murdach1232]

KA24E 2.4L engine Idles at 3-400rpms wont accelerate smoothly although if you press the accelerator slowly you can hold the accelerator at a place where it will rev up past idle then you can get it up past 2000 rpms

Have replaced the spark plug wires, plugs, cap and rotor, fuel and air filters, engine coolant sensor, fuel pressure regulator, throttle position sensor, fuel hoses, egr valve gasket, intake manifold and plenum gasskets, most of the vacuum hoses, pcv valve

Have cleaned and tested MAF sensor, Air temps sensor, IACV, AAV, EGRC -BPT valve, EGR valve, PAIR valve, scv valves and solenoid,throttle valve, vehicle speed sensor, fuel pump and tank filter, pumped out all gas and filled with fresh gas. Removed exhaust pipe from header and operated to rule out restriction.

I'm getting no codes, but the computer seems to be working because i can disconnect the various sensors and get it to throw the proper codes.

I have two questions to ask someone who knows:1. Some times when the ignition is on while the engine is off , there is a buzing sound. it goes away when i move the throttle lever. Ihave a stethoscope and the sound seems to be coming from the transmission.Is this normal it doesnt seem so.2. When testing the power transistor- the manual sez you should have infinity between terminals a and b, and a and c, but neither infinity or zero between b and c. what if you have a momentary reading, 120 to 180 ohms, then it goes to infinity? is the tranistor good? it costs $120, so i need to be sure.

MdMurdock