DodgeIntrepid.Net Forums banner

1 - 10 of 10 Posts

·
Premium Member
Joined
·
15,507 Posts
when you get a check engine light
 

·
Woober Goobers!
Joined
·
51,016 Posts
^^...x2
 

·
Registered
Joined
·
108 Posts
Discussion Starter #4
Just wanted to revisit this for a second, because it was recommended by another member here that the O2 sensors be changed to help with mileage and my hope was to reduce ping. Is there something that might be done to clean the existing sensors if they're fouled? Or am I over-thinking this?
 

·
Premium Member
Joined
·
17,328 Posts
FWIW, it has been said by others who know more about this than I do that the O2 sensors can drift a good ways from optimum oepration resulting in poor fuel mileage without setting a CEL/code.

But there's not a change interval official or otherwise. I'm still running my 2.7 on the originals with 250+k miles, and fuel milage is like it has always been (26-28 mostly highway).

So maybe until you get a CEL or mileage is suffering and there's no other explanation?
 

·
Registered
Joined
·
108 Posts
Discussion Starter #6 (Edited)
...or mileage is suffering and there's no other explanation?
That's pretty much it. I used to get upwards of 32MPG on my '99 with a 3.2, now on my 02 3.5 I'm lucky if I push 27MPG. Though I know that's as much as the car is rated for, the difference in displacement is disproportional to the difference in mileage. There's also some pinging at low RPMs under load (slightly hilly terrain and/or running A/C), suggesting that perhaps the mixture isn't right, ergo my suspicion that there might be an O2 sensor issue. Is there any way to test these things? Can they be cleaned in any way? I'd like to avoid spending the $100+ it will cost to replace them, if possible. But if I pick up another 5MPG give or take, it'd pay for itself over time.

Thanks for the feedback!!!
 

·
Registered
Joined
·
552 Posts
That's actually more than the car is rated for. There's also 100 different elements going on here, from tire condition/brand/PSI, to spark plugs, etc.

I consistently get 27.2 MPG on the highway on my Special and a lot of the 3.5 guys considered that a miracle.

You may get a tad bit more but you won't consistently hit 30 on a 3.5. This isn't an economy car, plus the technology driving them was designed in 98.
 

·
Registered
Joined
·
108 Posts
Discussion Starter #8
That's actually more than the car is rated for. There's also 100 different elements going on here, from tire condition/brand/PSI, to spark plugs, etc.

I consistently get 27.2 MPG on the highway on my Special and a lot of the 3.5 guys considered that a miracle.

You may get a tad bit more but you won't consistently hit 30 on a 3.5. This isn't an economy car, plus the technology driving them was designed in 98.
Understood, but would those variables account for a 5MPG+ difference between this '02 3.5 and my '99 3.2 which averages 32MPG? Besides, I've replaced the plugs with NGK Lazers, cleaned the throttle body and ran two bottles of Techron through it when I bought her in April.

Just seems that it could do better unless there's a substantial difference in the design between the 3.2 and 3.8 that I'm not understanding.
 

·
Premium Member
Joined
·
15,507 Posts
3.2 has different cams as compaired to the 3.5,, so , if everything looks ok,, your good to go, maybe your old 3.2 had 3.66 gears and the 3.5 has 3.86?? id say if you up over 25MPG,, thank the good Lord above,, I only get 25-27,,
 

·
Registered
Joined
·
1,803 Posts
FWIW, it has been said by others who know more about this than I do that the O2 sensors can drift a good ways from optimum oepration resulting in poor fuel mileage without setting a CEL/code.

But there's not a change interval official or otherwise. I'm still running my 2.7 on the originals with 250+k miles, and fuel milage is like it has always been (26-28 mostly highway).

So maybe until you get a CEL or mileage is suffering and there's no other explanation?
Yep! There it is!

I knew I'd find that jinx :D
 
1 - 10 of 10 Posts
Top