Hello, new to this forum, I have done a search and not been so lucky....


I have an 04 Ram 2500 Hemi quad 4x4, most of my driving is around town and I have been averaging 10.5 mpg. Recently it dropped from 10.5 to 8.7 in a matter of 6 weeks. Plugs and air filter are fine, as are tires and pressure,oil is change every 4 monthsand all other scheduled maint. has been done.It only has 34,000 miles, and the sudden drop has me baffled. Any ideas, is there a bad sensor or some kind of breather?

Thanks,
Karl

 

could be the winter mix fuel - but that would be a considerable drop - have you checked your tire pressure - that is the only advice or thoughts I have - I am sure someone smarter will chime in - 10.5mpg hurts enough - couldnt imagine 8.7mpg - goodluck

 

Yeah ,tire pressure is good, plugs were done months ago and mileage was fine, just a sudden drop in the last month or so,for no reason that i can see

 

Yes, tire pressure is good, just cant seem to figure out why the fast "big" drop

 

Might be a wheel bearing issue.
My mileage dropped just as my wheel bearing started making noise. Jacked it up and the tire was even hard to spin. Checked the brake pads and caliper but no problems there.
I also get poor mileage when it's cold out.

 

Karl,

While the winter blend might affect the mileage, the real cause is the cold. Since you are averaging only 10.5 mpg, I am assuming youmake a lot of short trips. The fuel mixture is rich until the engine reaches operating temp (or about 160F). Additionally, every 10 degrees drop causes an approximate 0.6 psi in tire presure. Since it's city driving, the od lock out again to the engine warms up has minimual effect. My 1500 local driving drops from approximately 12.5 to 11, but the city/highway mileage is little changed at about 16.

 

I dont think it is the temp. last three winters were colder and mileage never changed even with the winter fuel mix. I could jack it up and check to make sure the wheel spins free also.

I actually replaced the airfilter two weeks ago and only seemed to make it worse

 

Mine fell about 1MPG due to winter fuel.

 

I'm in the same boat - used to average 10-5 - 11, 4-5 weeks ago I dropped to a steady 9.2.

 

Had a simular problem befor. I went to diesel, the O2sensor went bad even diagnostics didn't pick it up.
I just bought 2007 diesel and there was all ready a recall on the O2 sensorsystem.
Even if I'm way off base it might be worth checking out.