hi every one my zx280 1979 wont work below 3000 or 2500 rpm
i changed the fuel pump air filter spark plug....
the car run good at high rpm but if i remove my leg of the gas pedel it well shut like if i cut the ign needd help

 

Sounds like the car doesn't know when it's in idle, or the idle is set too low. Can you give us a little more information on the car? have you downloaded the FSM that corresponds to your car yet? It's your greatest resource: XenonS130 - S130 Reference

EDIT:
Did you check the gap on your spark plugs before you put them in?

 

yup i checked the gap also i i have tried every thing in the afm ,,,

the car well eork for 3 sec and shut of the fuel pressure is ok and their is spark and the injectors getting puls i dont know what to do else

 

Give us a little more information here. Is the car Turbo? or N/A? Think about things that may have happened right before the car started to run poorly, did you replace anything? change anything?

With a little more info we can help guide you a little better.