Have you checked your air flow meter? I was chasing similar issues forever on my ‘94 (also a 12/93 build), replaced the AFM once with what what supposed to be a good used one. Didn’t change anything. After going through all the troubleshooting sequences, I came back to that used AFM and wouldn’t you know, it tested bad. Finally found another used one. Tested good, bolted it on, and it’s been running right ever since.