never worked on a */c engine but the evap purge has to go to the throttle body somewhere, maybe that vac line is leaking air

I think I see your problem, your air intake is very hot. That should be about 10* above air temp or so. When you put the FWI in did you install that IAT sensor in the intake or is it laying inside the engne compartment? It is very important that the PCM knws the temp of the air before it gets to the MAF, or is will set up the AFR wrong.

The IAT is installed correctly. That temp was after sitting in park with no movement for about 20-30 minutes

You're IAT shouldn't be cracked like that still. Hottest I've seen mine is at the track on a 80* day 10 passes, stock box. The temp was 102*

Installing a FWI should not effect your mileage. If it has, then something else has changed. Check all the vacuum lines.

Car will be under going lots of detailed investigation over the next few weeks. I have one theory that seems plausible at this point. The fuel pump was changed a few years ago before I knew very much about these cars. I bought the advance auto airtex pump which has always been noisy. Since the car never has a code and the problem came with the intake I imagine that crappy pump can't keep up with the extra air.

So can anyone tell me the specs of the fuel pressure? What should it be at key on, idle and under load?

About 48psi

Ok I will see about renting/buying one and enough hose to reach the drivers seat. I will update when I get some readings

Maybe you cracked you egr tube installing the intake?

this sure is a funny one, ive never had a problem installing a FWI, do you have a picture of your engine bay with it in?