Now running rough when cold after working in intake - '96 3.8L

I cleaned my egr ports in the lower intake to clear a P0401 code, Also replaced my whole vacum harness, DPFE & EGR. That seems to have eliminated the P0401 code but now the car runs rough (Idleing fast or dying) when cold started. After it warms up, it runs good. I also get a P0174 code now. I clecked all of the vacuum lines to see if that was the problem. I cannot find any that are loose or broken. When I had the upper intake off I sprayed some carb cleaner on the butterfies and the passages of the lower intake because they had a lot of buildup on them. I replaced the upper intake gaskets and cleaned the mating surface and torked the upper as the book showed. I am wondering if the Chemtool could have caused a problem?
Any Ideas?

Thank You.

You might try Berryman's B-12 Chemtool in the metal can.
My mechanic directed me to it, and it seems to clean that junk that seems to build up insid the "end cap" that is over the spray end of the fuel injectors.

One other thing to check....is the PVC line.....including the elbow at the top of the upper intake manifold.......mine got a crack on the inside of that elbow.

I had already checked the PCV line whith the other vacuum lines. It was OK. The thing that puzzles me is why it only happens when cold.