Bad MPG?!

[Dmoney2499]

So I drive a 96 ex v6, and I use to get about 285 miles to a tank of gas. Now I get about 200 and idk it all started about 2 months ago and my overdrive works and everything I even put fuel injector cleaner in it too same result does any body know why?

[vietkid_2006]

It's probably your O2 sensor.

[Dmoney2499]

It's probably your O2 sensor.

It effects the car that much? Like also i can kinda smell a lil oil/gas when i am not running the ac threw the vent but when ac is on I dont smell the gas fumes at all does it cause that too?

[James Matteu]

Yes, a Heated Oxygen Sensor (HO2S) can cause a gassy smell, but keep in mind that this may actually be a symptom not a cause. Visually inspect both HO2Ss. I use a 22mm closed end combination wrench to remove them, take the heat shield off first to get to the secondary (2°) HO2S. Look for any physical damage. Only buy Denso replacements.

On my car, the 2° HO2S is always the one that gets damaged when excessive unburnt fuel is dumped into the catalytic converter. The cat begins burning the excess gasoline and the high temps travel downstream and melt the 2° HO2S.

Let us know what you find.

[vietkid_2006]

With the gas smell you're probably running rich.

[Dmoney2499]

Yes, a Heated Oxygen Sensor (HO2S) can cause a gassy smell, but keep in mind that this may actually be a symptom not a cause. Visually inspect both HO2Ss. I use a 22mm closed end combination wrench to remove them, take the heat shield off first to get to the secondary (2°) HO2S. Look for any physical damage. Only buy Denso replacements.

On my car, the 2° HO2S is always the one that gets damaged when excessive unburnt fuel is dumped into the catalytic converter. The cat begins burning the excess gasoline and the high temps travel downstream and melt the 2° HO2S.

Let us know what you find.

Ok another quick question where is the O2 sensor so I can replace it?

[James Matteu]

With the gas smell you're probably running rich.

Yeah, this is that Air/Fuel chicken-egg question: is he running rich because of a bad HO2S or did running rich for some other reason damage the HO2S, which in turn is making the motor run even richer?

Ok another quick question where is the O2 sensor so I can replace it?

The 1° HO2S is mounted upstream relative to the Catalytic Converter, a few inches before it in fact. The 2° HO2S is mounted on the catalytic converter, downstream of the catalytic material.

[accordguy69]

i know this is off topic but quick question have u tried that tornado thing that kinda looks like a cheese grader lol it goes at the intake hose it like regulates the air flow there for giving you better gas milage. think it would work?? i just came across that nd i saw this thread.

[foamypirate]

i know this is off topic but quick question have u tried that tornado thing that kinda looks like a cheese grader lol it goes at the intake hose it like regulates the air flow there for giving you better gas milage. think it would work?? i just came across that nd i saw this thread.

It's a gimmick. Don't waste a penny on it. It does absolutely zip.

[accordguy69]

haha figures. dumb cheese graders =p