Any MPG value in changing Front O2 Sensors

[tbsbiker2]

I'm really really trying to squeeze some additional MPG's out of my truck...today (it's cold here in chicago) I filled up and was getting just over 10 MPG city driving and I'm not sticking my foot in it. I know I have a troubled rear O2 sensor that I need to get to P0140...but I am reading that sometimes changing the upstream ones increases MPG even if not throwing a code? Question is thats a pricey hail mary and is there any truth to it?

My other to do is going to manual hubs.

Thanks!

pete

[Chris.m]

I was under the impression that only the upstream oxygen sensor affected the air/fuel mix and the only real purpose of the downstream one was for emissions tests. So I don't really see how changing the downstream would help. I could be wrong though.

On a related note, you may want to look into a ScanGuage II. I just got mine about a week ago, but its tells you instant fuel consumption as well as quite a few different gauges like rpm, coolant temp, speed, HP (kind of a novelty)... I think theres a total of 37 that you could have with the X-gauge update. Anyway, it just really makes you easy on acceleration and tells you what your doing right and wrong to save gas.

http://www.scangauge.com/

[tbsbiker2]

Yes I was thinking the UPPER ones (which don't throw codes)...I have a hand held scan gauge but that one you linked to is pretty nifty..Might pop for the hubs first though...and go from there.

THANKS!

[Chuck Tribolet]

You should be getting better mileage than that. My '01 SE never goes below 13, and that's when I tow my boat.


Chuck

[Chris.m]

Oh yeah, I kinda mis-read that question.... I just had rear in my mind... but worst I've done in the city is 14.25 MPG if that helps

[Pathofinder]

Yes I was thinking the UPPER ones (which don't throw codes)...

There are CEL codes for the upper main 02 sensors.

Ive got the code happening to me right now!!

And for reference, I get 15-16mpg city, even with my main 02 sensor CEL code that is definetely not getting the most out of my fuel economy

[tbsbiker2]

well I continue to pound this old topic as Im doing my best to keep what I have and find a way to be at "peace" with the mileage as I have had Nissan Trucks/pathfinders since 1993. Its never done better than 12-13 in town and 10-11 in winter (I have driven it for over 4 years) New coil packs, religious oil changes with Mobil 1, all fluids...newer tires, etc...runs like a champ too. Not a funny noise, newer MAF (Maxima version)...so only thing I havent done is plugs? Maybe that's next. When my coil packs (2) went maybe they damaged the plugs a little but sure doesn't have any running or starting issues. And I had my mechanic do those and he said i was wasting $$ to change the plugs at 47,000 miles on that truck.

Sickens me to think I have some demon hidden in there killing my mileage (more than it already is based on original MPG testing).

[CanuckQx4]

Plugs are cheap for the 3.3L

I would definitely uncover that stone

[tbsbiker2]

3.5 liter...once it gets above 20 degrees here I'll pop for some new plugs and give it a go. Local shop wants like $400 to do them (3 hours labor)! says they need to remove the "top of plenium" forgive spelling..could be true but plugs are relatively cheap compared to the labor. I think they are stoned...a decent mechanic with the familarity and tools should be able to do this in an hour or maybe 1.5 hours tops.

[Chris.m]

My last idea - Do you have bigger than stock tires and/or wheels? That could make odometer show less miles than your actually going and provide artificially high fuel consumption.

[Chuck Tribolet]

It's worth checking the odometer vs. mile/km posts on the road.

Chuck

[Towncivilian]

3.5 liter...once it gets above 20 degrees here I'll pop for some new plugs and give it a go. Local shop wants like $400 to do them (3 hours labor)! says they need to remove the "top of plenium" forgive spelling..could be true but plugs are relatively cheap compared to the labor. I think they are stoned...a decent mechanic with the familarity and tools should be able to do this in an hour or maybe 1.5 hours tops.

Smells like s*** - you need to remove the throttle body to access the #4 spark plug according to the FSM, not the entire upper intake plenum. Though it wouldn't hurt to put threadlocker on your power valve screws (which you access by removing the upper intake plenum), but that's another issue entirely.

[Pathofinder]

You dont even need to remove the throttble body I dont get why people do that, you only need to remove the IACV which is only held on by 2 screws and there is enough clearance to squeeze it by

Iam a 37 year old mom with little to no experience turning wrenches and I did my spark plugs myself with a $25 tool kit in less than 2 hours, and I didnt even know where the plugs where when I started.

Look for another, HONEST shop

[ferrariowner123]

i have been wondering the exact thing about the O2 sensors, anyone else have any idea about that?

it got a little off topic toward the end.

[Pathfinder3.5]

I've got a code for one or two of my O2 sensors right now. This thing drinks gas like you wouldn't believe.