I have heard a rumor that replacing an old O2 sensor will increase mpg's. Can anyone confirm this, and if so, how hard would it be to replace it? Cost and availability would be helpful also. Thanks for any info.

 

I think your supposed to replace it at some thousand mile or so. Don't take my word for it as I have limited expirience with fuel injection engines. Never owned one, yet.

 

The o2sensor plays a major part in detecting if your engine is burning the right air/fuel mixture at that period in time from the exhaust of your engine. The sensor converts exhaust reading into a voltage which it sends to the computer. The computer then makes the appropriate adjustments if neccessary. I don't think that you would gain to much by replacing these. Usually if it is that bad to were you are losing mpg, most of the time it is malfunctioning and will throw a CEL. If they haven't been changed and the vehicle has high mileage I would go ahead and replace them. I just wouldn't neccessarily expect a big improvement in mpg. I beleive your year has two. I could be wrong about the gas mileage. If you change them let us know if it helped. It's good info.

P.S. Have you all ready done the basic tune up maintenance? This will definitely increase your mpg if it hasn't been done in a long time.

 

I didn't answer the rest of the question. I believe yours is on the Y-Pipe, but I'm not positive. I think the other one is is behind the cat. All it should take is an open ended wrench to take them off. I have 3 on my 96 and the hardest thing about them was getting the electric connectors seperated. Man I hate those plastic clips! You should be able to pick them up at any auto parts store. There are a ton of Fords out there so they should be pretty common. As far as price, it's been about a year since I replaced mine, I think they were right around $40 each. Don't hold me to it though.

 

The 90 Bronco only has one O2 sensor

 

Yes, replacing the O2 sensor will help with your performance and your MPG. As the exhaust passes the sensor, like anything else in the path of the exhaust, deposits build up on it and reduce the efficiency with which the HEGO/O2 sensor does its job. As with ANY electronic component that sends or receives microvoltages, age and extreme temperature changes reduce their efficiency.

 

Just letting you Know my experience. I threw a CEL R/R the 3 O2 Sensors and still got 14 mpg. You might get better but I know I didn't. I guess the results can vary case by case.

 

wish I got 14...still working on getting 8... Pretty sure the O2 sensor is the only sensor that degrades, rather than just quitting. If it is degraded it will reduce gas mileage, but a new one wont necessarily increase it....eekgads I am trying to make sense of that too..lol Replaced mine and performance felt better, but no big change in mpg. Though a a good day at the car wash can do the same for me..nuff rambling