Hesitation, pinging (slap, dance, torsional a-symmetrical movement, whatever you want to call it) sounds a LOT like a cam position sensor going bad. And no, a CPS will not cause ping, but is part of the cause-and effect; i.e. timing, unknown CP & limp mode, default timing, etc. If you romp on a car with a bad CPS, it will hesitate, then it'll run but will knock due to a lag in the timing. CPS's can be intermittent, or the detection range can be less than linear. May or may not throw a code too since the older OBD systems may have had longer latency times for errors to be recorded due to slow firmware.
Just my 2 cents, but I had the same problem & fixed it with the same solution as above... Pinging is one of the clues of... lean condition, excessive timing (either way), higher head temps, inadequate KI rating fuel. I mix 100LL avgas (about 2 gallons with a 16 gallon fillup) and yes the cats stink, but it runs reeeeaal nice.
M