1999 Volvo S80

I have an ongoing problem with my car. When stopped at a light or while in park my car pulsates and the lights fade in and out. I have had the mass air flow sensor, serpentine belt, alternator, abs sensor, battery, and hose from throttle to turbo all replaced and the car is doing the same thing. 5 lights were on (check engine, abs, stc, transmission, and service engine). All lights came off when taken to volvo dealership to have abs sensor replaced, but now car is having same proble, but no service lights are on. Please advise