Guys sorry if this has been answered already if so I cant find it:
Engine misses at low rpm around 1500 - 2k sometime violent miss on acceleration, stalls when switching to drive from rev or approaching a stop.
06 GR CARV 3.8 98K MILES
Pep boy diag - (only place close that was open) change plugs wires fuel treatment and Idle air motor - did all that and problem continued -finally threw a couple codes PO335 - crank pos sens a circuit performance - PO300 enginge missfire detected (no kidding) - PO339 - crankshaft pos sens circuit intermitent...
changed ckp and problem although intially better returned on test drive after about 4 minutes - no new codes - Symptoms again-
stalling from R to D
stalling intermint on stopping
bucking on gradual acceleration 1500 to 2000ish rpm not hard acceleration (has plenty of punch)

 

Did you test the battery (including a running full load test), and check the connections and cables?

 

A guess? Cracked flex plate. You have two codes pointing at the ckp sensor and another that eludes to it. You've changed the sensor. That leaves the PCM, wiring and the flex plate. The ckp sensor reads the reluctor slots on the flex plate as it rotates producing it's signal. If the flex plate is cracked it can wobble producing an erratic signal. Unfortunately, to prove it you have to get eyes on it meaning drop the tranny. If you're lucky there may be an inspection plate on the bottom of the tranny near where it bolts up to the engine or you may see something obvious by removing the starter.

http://www.obd-codes.com/p0335