Lately I have been suffering from pretty bad MPG in both my Tacoma and my Altima. I am hoping to at least solve the Tacoma problem here... After talking with a mechanic and talking about the problem, he and I concurred the problem might be the O2 sensors. My truck has about 120k miles. Even if they were not completely bad, I guess they were due for a change, so I went and ordered the Denso replacements that are same as OEM but dont come in the "little red box"...
Anyhow, fast forward to today. I have not installed the sensors because I have a feeling that they are not completely bad and I would be waisting $300.
Here is what is happening:
I am taking reading of voltage and temperature of the O2 sensors with my Ultragauge while I am driving.
Both sensors, Bank 1 and Bank 2 have similar readings. They are not aways the same, but they are usually close to one another, within 0.05 or 0.10 vot diference usually, until they both get to the same number. This tells me that one of the sensors might be going bad, since its taking a bit longer to get into the correct number. This is just me assuming.
I have no real way of knowing if what the Ultragauge measures is the Bank 1 sensor and Bank 2 sensor upstream or if its, 1 upstream and 1 downstream. If it was 1 upstream and 1 downstream that would mean my Catalytic Converter is bad right?
Anyone care to chime in and help me unravel this clusterfuck of a problem. I desperately need to fix my MPG problem but I do not want to waste money in parts that are working.
I am going to Seafoam the truck this weekend hopefully, dont know if that will do anything as my truck is very well maintained.
Thanks to anyone that chimes in.
As a side note:
- Spark Plugs should not be the problem, they have been changed twice and Ill prob change them again even though it should not be needed.
- Oil is Mobil 1 and gets changed often. I have a bad Valve Cover gasket, but that is going to be changed soon and should not affect this.
- Tire pressure is adequate.
- Gasoline was changed to 91 octane and used an octane booster to see if that was the problem. No change noticed.
- Transmission might need a bit of fluid. But it should not need much. I do find that in rare occassions I think it does not push into the adequate shift, but then again I feel the engine not working properly in those moments.
Long ago I got a code, it was for a Bank Sensor problem, I think. I stupidly did not write the code down and the code has never shown up again. Dont know if this helps any.