Got this car running a few months ago after throwing fuel pump, fuel filter, pressure regulator, injectors, plugs/wires, idle air control valve (had a high idle, stuck open). Also did the water pump and thermostat as the water pump was leaking. Anyway, it ran fine for a while, was able to drive it to the gas station and such a couple times. Went to start it one day, and it idled like absolute crap, almost to where I had to keep my foot on the gas to keep it alive. Managed to borrow an obd1 scanner from a co-worker and found a plethora of sensor circuit codes and some codes for an internal ecm failure. Replaced the ECM and none of the codes came back and it was running rough still but I didn't have to keep my foot on the gas. Still on the misfire track, I replaced the cheap amazon injectors I'd put in with a decent set of reman OEM ones and replaced the coils as well. With no change. Tested fuel pressure again today and it was within spec (41psi KOEO, and 39psi at idle), the other idea I had was to disconnect the exhaust before the cat to see if a clogged cat was my issue, but there was no change with that either. The exhaust will pop when I rev the engine and it definitely smells like it's running really rich. I'm absolutely stumped on what could be going on here. Watching live data on the scan tool, everything seems like it should be running great. I'm just curious if anyone else has run into something like this or can give me a direction to check that maybe I haven't thought about yet. Thanks!