So I've searched and read about these codes (one in particular seems very popular with our vehicles) and what the fix likely is when codes are presented by themself. But I have a couple together and my situation might be a little unique, hoping someone can help me look at some easier and less costly options first before diving into the bigger repair(s).

'02 2.4L Auto

p0421
p0401
p0442

Car is idling rough around 800 RPM, "bucks & surges" hasn't stalled yet but it shudders pretty solid, enough to rattle the hood.

Prior to these codes, I had to replace my air filter assembly as my old assembly cracked. It was cheaper for me to buy the chrome looking intake kits off ebay. I bought and installed that kit (link here) and had no issues. Fast forward a couple months and I throw these codes along with the idling issue, decide to check under hood. The sleeve connecting the intake pipe from filter to MAF sensor pulled away, car was basically sucking air straight from the MAF sensor. So I reconnect the filter to the MAF sensor adaptor, clear the codes, disconnect battery, but the rough idle remains (after ECU relearned) and codes are back.

Was really hoping that the filter assembly issue somehow caused some of these codes and it won't mean replacing the upper cat manifold but I'm not really sure where to start, could use some guidance here.