I have a 99 Volvo S80 2.9 w/99,868 miles. On the initial start up in the mornings it is very hard to start it will spin over several times and it will start if you give it pump the accelerator. After it starts it runs fine all day at all speeds ,but after it sits an hour or two it is back to being hard to start without giving it some gas.The fuel filter has been changed and the plugs have been changed.The ones I took out must have been the originals.The check engine comes on at times and says emissions system service needed are they referring to O2sensors or what? The starting problem is the biggest concern right now it is getting worse.Thanks Paul

Optional Information:
1999 Volvo S80 2.9

Already Tried:
fuel filter and spark plugs /p>