5lt misfiring and lagging

[vq5ltstato]

i just brought a vq statesman to find that when it gets warm it lacks power and misfires the owner before me just had the car serviced does any1 have any idea what it could be. some one told me sticky valves but i dont want to pull the heads of if that is not the problem..
thanks

[Not_An_Abba_Fan]

Depends on what was done in the service. I'd be checking for vacuum leaks, a faulty sensor either the coolant temp sensor or the air temp sensor, also check the timing.

[VrWagz1]

Sounds like timing is out a bit to me. Id check that first and go from there.