My 1990 twin tubo Nissan ZX run rough when idling have to keep foot on gas pedal! What is wrong.

If you paid attention to my particular vehicle in the garage section, you will find it is a 1989 300 ZX GS model, or the Z-31 type. I have no idea how to work on any model vehicle except my own make and year.

Is there any one that know the awnser!

Okay, start with the basic's. Change oil, spark plugs, distributor etc what have you done already? With out much information you couldn't expect much of an answer. For all we know it could be a bad fuel line, or maybe the fuel pump is on its way out, maybe the pumps fuse is faulty.

check the injectors, i think theyre supposed to ohm out between 10-14. common failure item on the early tts

had one. injectors are a very common problem. also, the adjustment screw in the intake could be out of place. check and see when the last time you had your timing belt replaced. a bad TB is very bad news for those motors.