'92 240sx gets close to stalli while decelerating, doesn't pass MA emission test

[rogue240sx]

I've searched and have tried several things. The car use to stall during deceleration all the time till I replaced the whole IACV unit out for a new one.

Here's what has been done so far:-Plugs replaced with correct NGK units-new plug wires, cap and rotor-swapped injectors, fpr, and fuel rail because i had an extra set laying around anyway-New OEM O2 sensor-New CTS-replaced the entire AAC unit-cleaned and inspected EGR, operates like it should-disconnected AIV hose going into the air filter to ensure no exhaust was contaminating my MAF-Ran several cans of seafoam through the fuel system and about a half a can through the intake and a third in the crankcase oil-reset the timing and idle-Regrounded the shared sensor ground with heavier wire.-car has a brand new magnaflow cat. haven't done an emission test with that yet but i doubt it'll solve my problem as everything is a bit high(NOx, HC, and CO) .

As of right now the car runs fine other than the rpms dropping way too low while slowing down in neutral or clutch in, and it will still stall if I have a lot of accessories running and I go on the brakes hard. RPMs return to the proper 700 reading after a few seconds. Another thing worth mentioning, when I activate the A/C the RPMs shoot way up to aprox 1500 but they still dip pretty low during deceleration and just slowly rev right back up to the 1500 mark again after about 5 secs.

I'm sick of this problem and I just want to get it resolved. It's embarrassing when you have to restart the car randomly, and I'd like to be able to pass emissions without cheating if possible. I know I could just run some alcohol through it to pass but I rather have the damn thing running properly.

[MaximA32]

Have you checked the throttle position sensor? How about the MAF checked that yet?