Does the O2 sensor after the cat have anything to do with gas mileage? - Toyota Nation Forum : Toyota Car and Truck Forums

darkneck · 02-23-2006, 07:00 AM

or does it just tell you that the cat is bad? I have a 95 camry 2.2 LE. There is one o2 sensor before the cat and one after.

Thx

ShawnM · 02-23-2006, 07:07 AM

Nope, its only purpose is to monitor the catylitic converter efficiency. It has no effect on gas milage.

darkneck · 02-23-2006, 07:15 AM

thanks alot. In that case I have no idea why I am only getting 18mpg. I replaced the sensor before the cat, changed the plugs, cap and rotor, fuel filter, air filter and thermostat. I check the ECT sensor and it is in spec. My consistent mpg is 18. I get more on my 91 300zx!! Does anyone have any other suggestions. I checked that the wheels turn easily and they do so there is no brake binding or anything like this. I have also changed the oil recently. Not sure if that would affect mileage. Tires are all filled to proper psi, ECT switch on transmissin is UP (off) and I do not drive it hard. So a heavy foot is not the problem. I checked the resistance on the ignition wires as well and they are also in spec. The CEL is not on. I am lost at this point.

Super Kaioken · 02-23-2006, 09:47 AM

try cleaning throttle body, and changing the air filter? maf sensor too i guess.

BlackCamSe · 02-23-2006, 01:12 PM

No just monitors the cat like emissions before and after the exaust runs through it

BlackCamSe · 02-23-2006, 01:15 PM

Quote:

Originally Posted by darkneck

thanks alot. In that case I have no idea why I am only getting 18mpg. I replaced the sensor before the cat, changed the plugs, cap and rotor, fuel filter, air filter and thermostat. I check the ECT sensor and it is in spec. My consistent mpg is 18. I get more on my 91 300zx!! Does anyone have any other suggestions. I checked that the wheels turn easily and they do so there is no brake binding or anything like this. I have also changed the oil recently. Not sure if that would affect mileage. Tires are all filled to proper psi, ECT switch on transmissin is UP (off) and I do not drive it hard. So a heavy foot is not the problem. I checked the resistance on the ignition wires as well and they are also in spec. The CEL is not on. I am lost at this point.

Try to run a bottle of fule injection cleener through a full tank of gass. Your injectors may be cloged

Mike Gerber · 02-23-2006, 05:32 PM

Your mileage doesn't seem that unusual to me. I have a 94 XLE 2.2 and I get around the same mileage this time of the year. I live in the Chicago area. You live in Long Island according to your signature. Is would guess most of your driving is city driving. I know you have oxygenated gas like we do here in Chicago. That too cuts down a bit on mileage. My mileage will go up to around 20 in the warmer Spring and Summer months but that's about it. The car was rated at 21 city and 28 highway when I purchased it new. 18 in the Winter months and 20 in the warmer months seems about normal to me.

Mike