Is it possible that you have changed the calibration of the Throttle Positioning Sensor? (..or maybe you still have water inside its connector..?) I have seen symptoms very much like what you are describing when one or both of the screws become loose.
The TPS is a black colored sensor on the outside of the throttle body right where the big black air hose coming from the air filter box connects to the silver part of the throttle body. It faces toward the firewall and has a rectangular shaped 4-pin connector. Additionally, it has 2 screws that connect it to the throttle body, and at least one of the screw holes leaves room for adjusting the calibration. (..I have attached a picture..)
Don't just replace it, check to see if it is mounted tightly, and then check to see if the connector is dry and plugged in all the way.
Good Luck.