Car slowing but engine reving...

[Howard_Woodard]

This is a 2002 V70 XC AWD w/2.4L Turbo.

The car was slowing down but my wife said that it gave her the impression that it was really pulling hard -- whatever that means -- and the tachometer was showing 4,000 RPM. That doesn't sound like "Limp Home" mode to me but I'm not sure that I know exactly what that's supposed to act like.

The Check Engine light came on. It had stored error codes P0234 (Turbo overboost), P0300 (Random misfire) and P0456 (small evap leak).

I figured that I would see some transmission error since the engine was revving much higher than what should be expected at that speed but there were only the three codes shown above.

Does this sound familiar to any of you? If so, what should I be looking at here?

Thanks in advance.