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Laredo2006 01-28-2013 10:01 PM

LOW MPG, should I change the O2 Sensors?
I am getting around 13.06 MPG and do around 225 miles per full tank. Is that normal for a 2006 4.7 4WD Grand Cherokee Laredo?

I should mention that I've putten winter tires on recently but still find it's crap.

Should I change the O2 Sensors and how many are there in total on this jeep?

Thank you.

PS> Anything else that could be giving me crap mpg?

jeepgcoman 01-28-2013 10:43 PM

Re: LOW MPG, should I change the O2 Sensors?
A few things, FWIW. Are your winter tires the same diameter and approximately the same weight as the stock tires/wheels? Is the tire preesure set correctly? Did this all start around September/October and/or when you installed the winter tires? Remember, winter fuels normally don't deliver as good fuel economy as summer blends. Are you using a different brand fuel, and has it been reformulated and/or does in contain ethanol?

Bottom line, I wouldn't jump at changing the O2's unless you have over about 75K on it. IMO, there are plenty of other things that should be investigated first. I had one go "lazy" on me at just over 60K, so I replaced them all. You may want to check out the thread I did when I began questioning O2 Sensor integrity:

Laredo2006 01-29-2013 12:05 AM

Re: LOW MPG, should I change the O2 Sensors?
Yes to all your questions, except for the change of brand of gasoline. My jeep has 125k miles on it and not sure if previous owner changed the o2 sensors before I bought it at around 105k miles 2.5 years ago.

I did start noticing a drop in mpg in sept/oct. I think all our gasoline tipoff artist stations have some ethanol will need to check.

Kayak83 02-03-2013 07:54 PM

Re: LOW MPG, should I change the O2 Sensors?
That's about the MPG I've always had.

05wkguy 02-08-2013 12:21 PM

Re: LOW MPG, should I change the O2 Sensors?
Alot of stations in the northern states and Canada switch to a gas with a higher ethanol contect for winter and that will make a small difference, about 1-1.5mpg on the highway.

Tires CAN make a difference, but only if they are taller than the stock ones. I had a weird situation happen were a wheel speed sensor went and caused me to get terrible GM (about 8 in town and 14 hwy). I didn't have a constant "check 4wd system" light on either, it would just turn on occaisonaly.

If all that checks out, then O2 sensors would be next on the list.

quicksilverado 02-18-2013 05:04 PM

Re: LOW MPG, should I change the O2 Sensors?
It is probably the winter blend gas. You normally lose 1-2 mpg. As soon as the summer blend gas is used it will pick back up.

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