Is my air filter responsible for my bad MPG?

Guitar RockHer · Jul 2, 2016

So I bought my Durango about 4 months ago from Autonation and they claimed to have done a 155 point inspection. They overlooked the air filter, I used to get 14MPG in the City and 23 on the Highway but it has recently been down to 9 City, 10 Highway. I took off my air filter and found it was black, stained and clogged with bugs. So I replaced it with a Wix Filter last night. Have since only driven about 5 miles and MPG is still the same, probably going to take longer for the computer to adjust. But is there anything else that could be causing bad MPG incase it isn't the Air Filter?

MWeed · Jul 2, 2016

Yes, an air filter can effect mileage. But I would hazard to say that yours is not yet the real cause of your low mileage. I think you have another problem. Maybe a slight limp from all the lead in your right foot? I think a trip to the shop is in order.

tomk · Jul 2, 2016

dirty air filters have much less effect on mileage than they did back in the days of carburetors.. on a carb, a clogged filter will restrict breathing AND make the engine run rich.. whereas with EFI it will just restrict breathing.. the mixture will still be accurate

dizzyD · Jul 5, 2016

I thought old oil caused MPG's to drop, but since synthetic that doesn't hold true to me anymore.

MWeed · Jul 5, 2016

I would suggest a trip to the dealer/repair shop for mileage in that range.

tomk · Jul 5, 2016

bad O2 sensors, clogged cats, transmission problems could all cause reduced mileage..

07Rango · Jul 5, 2016

Tomk, Wouldn't O2 Sensors, catalytic Converters, or Transmission issues all cause the CEL light to come on?

tomk · Jul 5, 2016

07Rango said:
Tomk, Wouldn't O2 Sensors, catalytic Converters, or Transmission issues all cause the CEL light to come on?

Eventually they will.. but the vehicle can run horribly with OBDII not registering a reportable fault.

This happened to me once with my wife's Lex.. I happened to take it for a ride (we don't often drive each other's vehicles), and I said to myself "Geez, this thing feels like it has a bad O2 sensor.." .. sure enough, a couple months later the CEL came on..

07Rango · Jul 5, 2016

I appreciate it Tomk. I may have to look into that.

tomk · Jul 5, 2016

Get an OBD reader that can show your long-term fuel trims ... and see if those look amiss...

Guitar RockHer · Jul 10, 2016

Thanks for all the replies! Have had a crazy week and forgot to check the forum. I had my ball joints replaced and my engine oil as well. Since then it's run better and I've had slightly better MPG. It runs perfectly though with absolutely no noticable problems, so maybe the MPG is just because it's a HEMI. Though I'll be flushing and refilling the transmission soon, so I'll see if that helps at all.
As a side note, I've really been wanting a K&N air intake for my car, mine uses the 57-1539 model, would this one work though? (No idea what model) https://sacramento.craigslist.org/pts/5652625794.html

beastofwar · Jul 11, 2016

Based on their website the 08 RAM 1500 with a HEMI uses 57-1533. It'd guess the bends in the tubing are different.

Is my air filter responsible for my bad MPG?

Guitar RockHer

MWeed

tomk

dizzyD

MWeed

tomk

07Rango

tomk

07Rango

tomk

Guitar RockHer

beastofwar

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