I have volvo 850 non turbo i am getting 15.9 mpg and a little bit concerned?

Question

All maintanence has been done and there is one thing
O2 senor has never been changed
car has 110K miles
Will it help? Why is check engine light is not on when o2 is not working properly?

Answer 1

If it is the O2 sensor that will definitely affect your mileage. If there is no check enginelight on. There me be a stored code, get the car scanned and she wcomputer scan says.hat the

Answer 2

for a normally aspirated 850 to only get 16 mpg it would have to be running pretty sick suspect coolant temp sensor/thermostat troubles or possible air mass unit problems [has check engine lamp bulb been removed?] the o-2 sensor could cause this but any of the above will have caused a code. if car operates normally and runs perfect you may be the victim of an abusive teenage driver [ it was funny how much more mileage my parents cars got after i completed building my first street car] good luck

Answer 3

make sure the thermostat is working and in good condition. if it is, have it scanned to see if its in its cold loop, or if its running right. if it is, then look at ignition, get rid of the platinums, bump the timing and run a comp test, wet/dry. id guess its starving for fuel and making no power, or making to much. is the tail pipe black and sooty when you rub your finger inside? or nice and dry grey. that'll tell you almost all. make sure your u joints are good or cv joints arent dry, this can gain 1 second in the 1/4 if they are in bad shape.