ok my car (check the sig) starts ok then after a few minnutes the idle drops and it shoots below like 300 then but to like 1500 and keeps doing this for awhile it does it randomly but i would like to fix it if anyone knows whats wrong with it please help its hard to not stall a stick if its already about to stall when it idles oh and its tbi just in case anyone needed to know

 

first thing i would do is check for vaccum leaks, may also be an egr problem.. maybe someone else has some other ideas for ya...