If you take a cigarette, and blow the smoke into the engine bay, you can see if there's a vacuum leak by the smoke getting sucked in on the intake side, and if there's an exhaust leak you'll see the smoke being pushed away from the exhaust leak ( you have to unplug your fans to do this...otherwise the flow from them will make the test pointless). I'd try to get my hands on a scanner if I were you, and clear the learned memory, and start over. If that doesn't work, pinout all the sensors that may affect this condition: TPS ( i know you said you just replaced it, but there may be high resistance in the wires somewhere), EGR (could be stuck open-but wouldn't affect anything while cruising), O2 (its responsible for your AFR), MAF (could be putting out false readings), ofcourse if you don't have access to any of these tests, or you don't understand what im talking about, PM or call me, and i'll explain it better. Does the car Idle fine?