high idle???

[flip]

Oh heres whats going on,have a 92 gt-40 motor, b-cam,svo-1.72 rollers, 24# injectors , cobra t/b, 73mm mas air, underdrives etc. Car runs on fast idle 1300-1500 for about an half hour depending on the weather, then it will idle down to about 850 and then for no reason will return to the higher idle, tps is set iac is new , fuel pressure @ idle is 40, could this be caused by the tab/tad ? any help will be appreciated as this is driving me nuts

 

[kndyblucapri]

your idle control is probably the problem it's on your throttle body remove it and push in that cone see if it's seized up even if it moves it might be f-ed up so you might want to replace it or try putting in a used piece and see if it is still doing it