Well if it is not a vacuum leak, and your FPR is ok there are a couple things I can throw at the wall.

Disconnect the negative terminal and then Unplug you AMM. Reconnect your battery negative and see if that changes how the engine is running when you start it. Most likely should be rough but if you had a AMM issue, that would affect your Fuel/Air Mix.

Have you cleaned the Throttle Body and checked all the hoses for cracks or leaks?

Check the vacuum lines going to the Vapor recovery system from the top of the throttle body, are they in good shape with no leaks?

Have you checked under the big intake hose for holes or tears on the bottom side. A leak there can throw off the AMM air mixture reading and make it run like crud. Never had one that bad but may be worth checking.

Good Luck,

Paul