leaky egr pipe

[turbomsp2003]

I just put my car back together after a long wait for my lsd to come in from protege garage and now its idling like crap my obd2 monitor and my vac gauge say I'm at 27 vacuum so its not that the only other thing it could be is that the egr pipe that connects at the header is leaking slightly but it won't tighten anymore....could this leak cause my rough idle and p0171 code?

 

[thecrash91]

sounds like a vacuum leak to me, check all of your vacuum hoses

 

[turbomsp2003]

I've checked and rechecked them can't find any leaks and vacuum gauge is reading 27