P0171 and P0174
 

My 2007 Five Hundred popped these codes a while back.

My long term fuel trim is 25 or so at idle and goes down when I hit 3000rpm.

I have changed the EGR valve, MAF and fuel filter.

I also had Vacuum and smoke test done. Along with using Starter fluid spray to look for leaks. Nothing was found.

They also said the fuel pump was putting out good pressure.

This all started around the time I ran some SeaFoam through it. I've done Fuel injector cleaner through it since then.

Should I take it to a dealer to check injectors? I'm out of ideas.

Advice, greatly appreciated! Thanks.

Those codes are usually indicative of a vacuum leak.
The proof of it in this case is the fuel trim that is adding fuel at idle and correcting at a higher RPM speed.
Not all intake manifold gasket leaks will show up with a smoke test. What you can try
is to remove the oil fill cap and note if there is any kind of change in rpm, if so the gaskets are leaking on the inside where the MAF can't tell , but the fuel trim can and adds fuel to compensate.

Similar situation. Cannot find the leak
 

I will try the oil cap test and see if that does the trick. I also suspect the pcv valve is NOT seated correctly as I can pull it out/push it in very easily.