I'm apt to think it might be your servo, I had a similar problem with the 322 also, It for some reason lost it's center point under certain conditions and drove me nuts trying to figure it out, I changed the servo to a HS425 and it went away, I only use the 322's and others in it's class for throttle now, Better servos are cheaper than new planes. The 322 is a good sport servo but lacks when it comes to higher performance taskes like a screaming fast 500. Another club member had one and that thing moved.

Dauntae