been back and fourth with this car for a while now, 91 si with z6 swap, throws a code 14. hooked up my smoke machine and found a vacuum leak, fixed the issue, same thing, code 14, and when the manifold pressure equalizes it just spudders, revs and quits revs and quits, idles fine, only between 1200-1800 rpm does it happen and its only when pressure is equalized, if i am accelerating or idling it's fine. any ideas? pcm is good, no more vacuum leaks. just looking for thoughts and ideas here.

 

Have you tried a know good working iacv. Have you checked for voltage at the plug?

 

whats voltage @ the plug supposto be? i will be getting a brand new one friday.