Code came up on smog what do it do.

PO300 and P1399 are random cylinder misfire detected.
PO301 cylinder 1 misfire
PO302 cylinder 2 misfire
PO304 cylinder 4 misfire
PO306 cylinder 6 misfire
I would say that you have damage to the ignition wiring harness or you ECM is failing.

I've had similar issues. The fix I used was to take my vehicle to AAMCO and let them run a diagnostic check. Most often it will be at little or no cost and, if you don't want to mess with the fix anymore, they can fix it onsite.

code po306 refers to cylinder 6 misfire detected===causes ---engine mechanical fault--wiring--ignition/ fuel system--injector--ECT/MAF sensor--ECM

the pressure is good so rule out mechanical fault
injectors being cleaned and tested so rule out injectors
fuel pressure not tested to see if it is average or minimum
check MAF sensor for correct voltage and/ or resistance
IF the misfire moved when the plug and wires were swapped then check the wires and connections . If not then check distributor cap for crack or dirty in side the cap allowing shorting of the HT spark

slite posibility of head gasket leaking a little or could be a worn piston ring you have changed every thing else

code po306 means cylinder number 6 misfire detected, possible causes air leak in the intake manifold or in the egr or pcm system, could have mechanical problem number 6 cylinder like burned or worn valves,could have clogged fuel injector or faulty fuel injector,could have bad ignition coil, bad spark plug or bad spark plug wire.

P0430 code is(catalyst efficiency below threshold on bank 2)
P0420 code is((catalyst efficiency below threshold on bank 1)
P0306 code is(cylinder 6 misfire detected)

These are misfire codes.This means that your vehicle is missing.The 300 is a random misfire and the 305 is for cylinder 5,and the 306 is for cylinder number 6.Check the plugs if they are good then you could have bad coils.They are top of the plugs.Hope this helps.Good luck.

the bottom crank pulley is either lose! the keyway sheared and vibrateing against the crank sensor or the bolt in the crank pulley has backed off or fell out

P0301 = Cyl no 1
P0306 = Cyl no 6

If you have changed plugs and leads and confident that they are now ok you need to run a compression check on all the cylinders, I'd emagine they should all be running at approximately 150psi per bore, if 1 & 6 are down it could be the head gasket, timing or piston rings.

Plug, plug wire, plugged or open fuel injector. are the most likely.