Ok, so basically my gas mileage has been getting so horrible that I HAVE to find out whats wrong.

So when I bought my rig 2 years ago, I was averaging around 16mpg with that constant romping on her, well overtime I started slowing down and now, while I may speed a bit, its not W.O.T. constantly or rarely at all. But i'm getting even worse gas mileage, im talking 8 mpg!

It's been having horrible mpg like this for over a year now, and in the last few days its gone up to 11mpg with same driving pattern, but it does this occasionaly. But what is making me get such horrible gas mileage? My air filter is clean, i need to replace my plugs with regular champions but I was already getting this horrible mpg before I changed them to iridium and everything else is up to date.

I THOUGHT I found the conclusion of that it would be the 02 sensors being fouled up and whatnot, everything basically pin points to those so I though. But I called a well known shop today and they said if it WAS the 02 sensors, I would have a check engine light on, which I do not. I was refereed to another shop but they want 45bucks just to find the problem, I dont have that money.

Cant someone help me try and find the problem I cant live with this horrible gas mileage anymore, its making me more dirt road broke. Help please.

Its an 02 slt+ 4.7 stock with slight weight reductions with 70k miles. Thank you.

Also I was told it could be the vacuum pump that might be the problem, is that a possibility? Thanks.

 

1) not all shops know what they are talking about, the O2 sensors on these trucks are known to fail without setting off a CEL, they are your most likely culprit

2)irridium plugs wont be the cause of your problem, you should be able to leave them in. unless they are worn down out of spec.

never heard of a vacuum pump on these trucks, thats usually more of a diesel thing afaik (and i couldnt find one listed in the parts manual

 

Yeah O2 sensors fail a lot without CEL coming on. If you find the spec you can do a resistance to test if they are good or not.

 

Thanks for your help, I think im going have a shop check the sensors out.

The 02 sensors were the big thing that I though would be the problem, it would make sense as I have had all the issues as if the 02 sensors WERE bad. Such as the obviously horrible mpg, strong sent of gas especially on start up at times, and slight bucking at times especially on freeway. And then I also new the 02 sensors were famous for having problems in these trucks too. So if my problem IS the sensors, how much money am I looking at on having to spend here for new sensors? How much money is it to get them replaced (or is replacing them a simple job, any special tools?) Thanks.

 

The sensors (yes there are two of them) are about $30 bucks a piece. There is a upstream and a downstream sensor. As far as install, i don't know your skill level but, generally anyone who has the ability to use a wrench can do it.. they just unscrew out of a threaded hole and the new one just screws in where the old one was...

Not sure of the location of the sensors on the 4.7l but, generally one is somewhere near the motor on the exhaust pipe and one is under the truck after the cat in the exhaust pipe


hope that helps!

 

here is the thing, it depends on which emissions set up your truck has, the california emissions has 4 O2 sensors and the regular one has 2.

now you should only need to replace the pre-cat(before the catalytic converter, closest to the engine) sensor as this is the one which controls the A/F mixture, the post cat is just there to monitor how the cat is doing.

changing them is as simple as turning a socket wrench, if you can do that you should be more than capable of changing the sensors.

they range in price from $30 - about $80 a piece, your best bet for compatibility and making sure it works right is to buy from the dealer, some aftermarket sensors disagree with these trucks for some reason

 

+1 SS.

Get real Mopar replacement O2 sensors (2 or 4 depending on your setup) AND a new PCV and you should be set.

IndyDurango

 

I just wanted to add in, I was having this same problem with my '03 Durango. After a year mine was getting almost half the milage from when I first got it. My quick fix was stop letting my wife drive it and get her, her own Kia. Now it gets GREAT milage!

 

I remember reading that my rig was equipped with four 02 sensors, but now im hearing that's only in ones that were produced in cali, my rig has always been in oregon so i'm only running two 02 sensors correct?
Also, can someone pin point in a picture exactly where the sensors are? thank you. And can a parts shop (such as advanced auto parts) be able to test the sensors? Thanks.

Also, where can I find the CHEAPEST mopar brand oxygen sensors? I'm finding them for 80 bucks 0.0 , any place cheaper?

 

I read that Dodge used Denso O2 sensors at some point if not now, so you can probably save some money by just buying one of those.