My 93 Toyota Pickup starts perfectly fine when it is cold but once the motor warms up and you cut it off and wait a few minutes it takes a minute for it to start, and once it start it has a very low idle at about 400. The whole upper and lower intake have been clean, throttle body adjusted right, new coolant sensor and throttle position sensor that is set right. Could it be the idle air control valve? Or what else could it be?