I just replaced the engine on my 2006 Volvo s60 2.5t and i am concerned with the result. The car is not as responsive and feels really down on power. I checked to see if there was to much oil in the engine and there was, but only about a half a liter. Would this cause such a drastic loss in power? Is there anything else that could be causing this problem?.

 

Not enough boost from the turbo, and since there is no boost gauge you will need the scan tool to check it.

 

Try to replace the TCV valve, If you know someone who have a S80, S60 or V70 turbo its easy to just borrow the TCV valve and see if it makes any difference.

 

I'd start with the basics first . Check compression,plugs, clean MAF sensor, check fuel pressure and regulator along with all related boost items. Plumbing and so on. Running a vac me gauge can revile a misfire all sorts of issues. Even PVC ....
I've also had bad injectors spraying a stream instead of a fine mist. Caused a rich flooding condition on two cylinders.