TLDR at bottom) Hello everyone one, I'm an aircraft technician and have a basic understanding of working on cars, I bought this car from a used car auction place and has 199170 miles the problem started after I replaced the egr valve and it struggled to maintain a good idle and if left on long enough will choke and the engine dies out, also doesn't do it when it's cold outside, I originally got misfire codes, so replaced the spark plugs and coils and it still idles rough, I gave up on it and decided to just not let it idle to prevent damage to the catalytic converter, because runs fine when going above 15mph, so if auto stop doesn't engage I turn off the car at stop lights (I am aware it's not the best solution especially since it'll wear out the starter), it also chugs sometimes when I accelerate from stop, but I want to try and fix it now so if anyone has an idea let me know, so far I did a diagnostic test and it seems to be running air rich, and probably a fuel system issue, I don't think it's the fuel injector because it didn't show a consistent misfire in the cylinders so I'm thinking it's fuel pump but also read it could be the maf but the obd reader showed it working, and heard it could be the pcv, any direction would be awesome

TLDRcar idles rough only below 10-15mph, sometimes chugs from stop, when cold outside doesn't idle rough, lean fuel/air mix, air rich
Replaced the following:
EGR
Coils
Spark plugs

Thinking possible cause most to least:
F​​uel pump
PCV
MAF Sensor

 

Return to this step. Figure out what went wrong. A leaky EGR valve will do exactly what you describe.

 

I'll take a look in a bit when the weather warms up a bit, I'll keep you posted
UPDATE: I took off the EGR, inspected the seal it's good, took the multimeter to it, no issues found there, retorqued it and when I started the car the first time it stalled, second time it stalled third time it was able to start, and after that also starts, it currently starts at 1500 rpm at idle smooth, then over time drops to 1000 and below and begins to be rough again

 

Still could be leaking across the valve. I would try a block off plate under the EGR valve just to eliminate the valve as leaking. Leave the valve pluged in so you don't set a code. Just some shim stock or other thin metal sheet between the head and valve.