Just to confirm. You replaced the PCM and still have the exact same symptom?
Do all of the cylinders fill with gas or just one?
However, if injectors are being held open and it's not a bad PCM, then the next most likely cause is a short to ground in the injector return signal wire. Do you have a "noid" style test light to confirm firing pulse across each injector?
It's always a good idea to post the full DTC codes. There are 1,000's of them and they each have a story to tell.
But if looking for an educated guess, for the 1996-1998 model year the O2 heaters draw their power through the PCM. Perhaps there's something going on with that circuit. Suggest disconnecting all (4) O2 sensor electrical connectors to see if this changes the symptom.