1990 Mazda Miata Runs Idle Very Low 250 Rpms Wont Move Unless U 4000 Wonts Shut

i have a 1990 mazda miata it runs but idle is very low like 250 rpms and it wont move unless u have rpms at 4000 or it wonts to shut off i changed mafs and checked timing ive checked the ecu and the injectors i dont have any clues of what else it could be and i have no check engine light on so im thinking something mechanical.