at almost any speed it misses/cuts out/bucks/backfires sometimes... on 1994 Ford Ranger

changed fuel filter-mass air flow-purge-trans speed-plug wires-replaced cracked vac fittings

Asked by for the 1994 Ford Ranger
Has it ever been scanned for codes and had 'live data' monitored to aid in proper diagnosis? STOP replacing parts without info on what the PCM is seeing!
I have a code reader on the koeo test all is good no codes