Is your booster pump working? Disconnect the Polaris and see if the water stream coming out of the wall is much stronger with the pump on versus when just the main circulating pump is running. IF the flow/pressure is not much greater there is a problem with your booster pump, if it is strong then the problem is the polaris itself. Do the wheels all turn or just one side? If one side only you may have a broken belt.

There are some adjustments, check the online manual about timing the wheels. Hate to bring up another possibility. Are you loosing water from the pool? I just ditched my 380 after 8 years as it was doing what yours is doing, but I was loosing a lot of water when it ran -- turns out there was a break in the line between the pump and the wall connector. Rather than spend a lot of money digging up the concrete I bought a Dolphin.