How much would these affect my gas mileage?

[Xbox2202]

Ok, I got my car scanned cause it's getting horrible gas mileage (around 11mpg). So it came up to be right oxygen sensor failure and egr problems. How much will these cut my gas mileage down (seperately and together if possible)? I'm in the process of changing out for a new oxygen sensor right now.

[Rally Sport]

Well EGR just deals with emissions from what I understand, and the oxygen sensor sounds like the only problem with gas mileage because your engine doesnt know how much fuel to throw into the mix so that would definately be the cause of low MPG..

[wrightz28]

o2 sensor readings make a HUGE difference on mileage. Like Rally said, EGR jsut regulates NOx gasses beck into the intake to clean up emissions. But, a bad egr could casue preigniton and the PCM will go nuts on ignition timing.

[NRFDBeliever]

Sometimes the bad egr readings will be caused by the bad o2 sensor. replace it and have it checked again to see if you are still getting the egr reading.

As was already said, the o2 sensor has a huge effect on mpg.

[ZL1power69]

a bad o2 may dump more fuel into the engine, causing an excessively rich condition that will kill the gas mileage. that can also cause the egr to become plugged up with carbon and will also hurt gas mileage. replace the sensor and pull and clean the egr valve and reset the computer.

[Xbox2202]

Ok, had the o2 sensor changed out today. The shop had to heat the sensor up with a torch to get it out. I have to wait till it's dry out to reset the computer cause I have to take my desktop outside to do it. I ran the car today without reseting the computer and it's still getting horrible gas mileage, so will it run like it's got a bad sensor until I reset it?

I've scanned the car and the only things coming up on it the other day that could effect the gas were the egr and o2 sensor. Is there anything that could cripple my gas mileage like this without showing up on the error codes?

[wrightz28]

improper tire inflation, poor alignment, leaking injectors/fuel pressure regulator, bad coolant temp sensor, idle air motor, 300 lbs worth of garage sale junk in the trunk, heavy right foot are the biggest killers.

The new o2 should clear things up right away (within a few miles to reset fule trim) without any resetting the ECM.

[Xbox2202]

I hooked the car up today and the egr and o2 sensor codes are gone already. So I guess the egr was messed up because of the o2 sensor. I just reset the trouble codes so hopefully it will do better now. Will it correct itself now or will I need to reset more then just the trouble codes?

[ZL1power69]

computer should completely reset itself within 15miles of drive time. if the codes do not reappear after 15miles then u should be ok

[viperh]

If you don't have emission block off your EGR.. I dont remember off the top of my head how my 02 sensors you have if you have four replace the front and buy o2 sims for the rears if you only have two replace them both might as well while you are in there.