I have a 2005 Civic 1.7L with 165k miles. It's getting bad gas mileage. I was thinking of replacing the O2 Sensors and the MAP sensor. Comments, any suggestions?

 

How bad are we talking?

 

Its my granddaughters car and she does not track her gas mileage so I don't know exactly but she is complaining and thinks its pretty significant. We got the car a few years ago so I don't know a lot about its history. I replaced the timing belt, axles, brakes, cam position sensor and front suspension. All that stuff was original so I assume everything else is too. I am thinking maybe the o2 sensors, MAP sensor and maybe the coils should be replaced.

 

You should also check of the EGR plate/EGR valve needs to be cleaned out.

 

Add spark plugs (use OEM NGK) and air filter to your list. Check for sticking brake calipers. Check tire pressure.