I would start by resetting the SAFC to ZERO across the board. You don't want it doing anything while you're troubleshooting. I don't trust those as far as I can throw them. Especially not on these cars.

Beyond that, do you have any codes? A dead O2 sensor can lead to a default fuel map that's inherently rich to save the engine, but that should come with a CEL.

Another bastard that will lead a parade of gremlins down your street is the CLT (coolant temp sensor). ECU uses coolant temperature at the radiator cap to determine fuel trims. Think warm up, enrichment mode. When these things fail, they tend to tell the ECU that the engine is -255* or so, resulting in the ECU doing everything it can to warm up. This isn't as noticeable when it's actually cold outside, but it can drive you crazy in the summer.

Beyond that, if it's been a while since you replaced the timing belt, or if you re-used the hydraulic tensioner last time you did, I have seen them gradually fail.

Loss of timing is catastrophic when the belt fails instantaneously at speed, but when the tensioner goes, timing slips away a bit at a time. Lose a half a tooth or so and idle gets rough. Loose a tooth or more and it starts idling like a POS Harley. Lose much more than that and it just wont start anymore.

Good luck sir.