Volvo: 1995 Volvo 850 GLT Misfire, volvo 850 glt, o2 sensors

Question
My Vovlo misfires at all speeds.  It seems to be worse at slow speeds.  The RPM's will go up and it will jump, etc.  and it seems as if it isn't getting the gas.  And then sometimes it will run smoothly.  If I let it idle in park for a few minutes, the check engine light will come on and then go off after a day or so.  Could this me my O2 sensor or fuel filter? Can an O2 sensor be cleaned?  If so, what should be used to clean it?

Thank you so much for any help you can provide.

Answer
Barbara,
You need to find that missing problem. That might be low fuel pressure, distributor cap, rotor, ignition wires, or plugs. I do not think that it could be the O2 sensor, and a very small possibility the fuel filter. O2 sensors can not be cleaned, if it is bad it's needs to be replaced. Since your car uses two sensors if one goes out replace them both, using original Volvo O2 senors. No aftermarket or parts store ones.