I was getting p0171 code, and couldn't find the vaccume leak, changed my plenium and intake gasket and ran much better, although still stumbling. Could rusted pipe in the exhaust cause any of this. gettin air i guess from somewhere, any suggestion's at this point, thx mjz

 

If you are still having a vacuum leak an easy way to find it your self is to get some break cleaner or a can of eather and spray around vacuum hoses and intake manifold. If you find a spot that is leaking the engine will idle up for a second. From there you can pin point the leak.