Horrible gas mileage whats the cause?

[sgarlic]

Changed my oil about 300 miles ago and I only run BP and citgo if I have too.Wouldn't bad o2 sensors give a code? I had the car scanned not to long about and they said the o2 sensors were a little weak but still good and that was less then 4k miles ago. can you change just the front ? I have four right?

Lol. Was this a Ford dealer that told you they were "a little weak?" I've never heard them described like that.

It may not throw a code unless they are actually malfunctioning. If they have deposits all over them, they may not be sensing as accurately as they did new.. perhaps that's what they meant by weak.

 

[Jester73440]

Lol. Was this a Ford dealer that told you they were "a little weak?" I've never heard them described like that.

It may not throw a code unless they are actually malfunctioning. If they have deposits all over them, they may not be sensing as accurately as they did new.. perhaps that's what they meant by weak.

No it was a shop I had a code and i took it in to get it scanned and my MAF had a fuzz ball on it because my air filter wasn't in right. Is there a way to clean the o2s?


And the 5.0 will lay down the labor day burn out

 

[Dark Knight GT]

Changed my oil about 300 miles ago and I only run BP and citgo if I have too.Wouldn't bad o2 sensors give a code? I had the car scanned not to long about and they said the o2 sensors were a little weak but still good and that was less then 4k miles ago. can you change just the front ? I have four right?

You shouldn't have but two front o2 sensors, and yes, you can change just them. As for giving a code, sometimes, but not always.

Well then I would wait till your next oil change to use SeaFoam in the crankcase but you can still use it in the gas and the intake.

I'm no expert on Seafoam, but I'm pretty sure he could still use it in his oil and not have to change his oil immediately following. Seafoam is a petroleum product and is a cleaning agent. No where on the can does it warn(or at least that I've seen) to change your oil following it's usage. Though I'm imagining it would be best to do since it might break loose a lot of dirt and sludge that would clog the oil filter.

 

[Kilgore Trout]

I think it is best to put only about 100 miles on oil that has Seafoam added to it...

 

[derek02gt]

I did a offroad xpipe like last year and never got o2 sensors..my gas has been pretty crappy but Ive procrastinated to order it. could this be the reason? what do o2 sensors actually do?

 

[Kilgore Trout]

http://en.wikipedia.org/wiki/O2_sensor

 

[04gtdrop]

the o2 sensors, read the exhuast that comes out of the engine. the look for the a/f ratio ( i think). they are in place to make sure that you dont run too lean or rich. kind of like a check point i think. maybe some one else with a little more tech experiance can chime in.....

 

[Kilgore Trout]

I think the WikiPedia article I linked to covers it pretty thoroughly...

 

[sgarlic]

Fronts: Monitor the A/F mixture and provide results to the computer so it can adjust.

Rears: Monitor the catalytic converter and emmissions efficiency, and throw a check engine light if readings don't match within the range of what is specified.

 

[derek02gt]

so me not installing o2 simms with my offroad setup is probably the cause of my crappy gas mileage?

 

[jstreet0204]

so me not installing o2 simms with my offroad setup is probably the cause of my crappy gas mileage?

No, front o2's can cause bad mileage, not rears.

 

[derek02gt]

isnt the xpipe connection considered the front? i mean, it is at the front of the car..let me know as something is definately wrong with my car..a full fillup which gives me like 15.5 gallons will only give me 215-230miles on the tank..it sucks..

 

[Dark Knight GT]

The front o2 sensors are the ones closest to the motor. Once you're under there, its not hard to figure out which is which.

 

[Jester73440]

Well I changed my plugs today and the old ones looked great. If my car was runnig rich from having bad o2 sensors wouldn't it show on the plugs? I mean they were whiteish which makes me think its not runnig rich at all. Could something be dragging the car down i checked the brakes and nothing is locked up. I watched my speedo and when i let off the gas the mph does not drop fast. On the highway doing 70mph I'm at like 2k rpm. so does all this sound right or is it everyone as stumpped as I' am?

 

[Dark Knight GT]

I'm kind of as stumped as you are. I honestly don't know what else to suggest. It could be the humidity levels where you live are just bad ?