Recently we experience a loss of power followed by lurching. This may happen two or three times during an hour drive. Usually during acceleration. We recently had the car tuned and the plugs replaced. The s60 has 101,000 miles and is a 2005. Any suggestions on what we may be dealing with? We told the service manager about the problem before he tuned the engine.

Thanks

 

If you can revert to stock ECU mapping and see if the problem persists would be ideal so that you may rule out ignition faults. In the latter case try replacing the ignition coils...
Good luck.