Changed Air Filter, mileage went down the drain

I recently hit the 19,500 miles, averaging 18-19 miles per gallon. I get this gas mileage babying the gas pedal in about 50% city / 50% freeway.

Before I changed the filter, the gas needle was a hair below the half way mark and at 200 miles. After I changed the filter, I noticed that my gas needle was heading to 'E' quick. Tonight I filled up, and I only averaged 14.56 MPG.

Has anyone noticed such a dramatic drop in throttle? Tire pressure is set to about 38 PSI. I'm using a Purolator Air filter. I've been extra gentle with the throttle, figuring that the computer might be adjusting to the air flow. Should I have reset the ECU after the filter change?

Any input would be greatly appreciated.

I recently hit the 19,500 miles, averaging 18-19 miles per gallon. I get this gas mileage babying the gas pedal in about 50% city / 50% freeway.

Before I changed the filter, the gas needle was a hair below the half way mark and at 200 miles. After I changed the filter, I noticed that my gas needle was heading to 'E' quick. Tonight I filled up, and I only averaged 14.56 MPG.

Has anyone noticed such a dramatic drop in throttle? Tire pressure is set to about 38 PSI. I'm using a Purolator Air filter. I've been extra gentle with the throttle, figuring that the computer might be adjusting to the air flow. Should I have reset the ECU after the filter change?

Any input would be greatly appreciated.


I recently replaced my air filter at 34,000 miles for the first time with a Honda part. No noticable change in fuel economy.

I recently hit the 19,500 miles, averaging 18-19 miles per gallon. I get this gas mileage babying the gas pedal in about 50% city / 50% freeway.

Before I changed the filter, the gas needle was a hair below the half way mark and at 200 miles. After I changed the filter, I noticed that my gas needle was heading to 'E' quick. Tonight I filled up, and I only averaged 14.56 MPG.

Has anyone noticed such a dramatic drop in throttle? Tire pressure is set to about 38 PSI. I'm using a Purolator Air filter. I've been extra gentle with the throttle, figuring that the computer might be adjusting to the air flow. Should I have reset the ECU after the filter change?

Any input would be greatly appreciated.
My mileage thread shows the same thing happened to me. I have also heard of this from one other member. Very odd indeed. :confused:

I replaced mine filter with the oem one from H and A.

BTW, if you have a few weeks to kill, do a search for "gas mileage"

I just installed a K&N in my '07. I've used them in all my (currently 4) cars for years. One on my cars has 130K on one. They go in and you clean them every 50K mi. They're supposed to have superior thru-put.
TomJV

I just installed a K&N in my '07. They're supposed to have superior thru-put.
TomJV

Have you used half a tank of fuel yet like the op so you can give a definitive mileage gain figure?:rolleyes:

Yikes, I just replaced mine on my '06. I will keep an eye on it.

BTW, if you have a few weeks to kill, do a search for "gas mileage"

Ain't that the truth.

I replaced my air filter with one from H&A and haven't noticed any change in gas mileage, but I've only been through 1 or 2 tanks since I changed the filter. I'll try to note my mileage next time and see what I get. I think I got around 17 last time in 100% city (suburbs) driving. I've got a 12 mile commute with maybe 5 or 6 lights at the most between work and home, so I'm usually cruising 1, 2 or 3 miles at a time without having to stop.

Are you sure you have it in the right direction? Some of these filters have one way flow specs.

Are you sure you have it in the right direction? Some of these filters have one way flow specs.
Because of the notch, it can only go in one way. (green side down)

I got an oem filter from H&A at 20k. now at just under 25k still getting around 20-22 mpg. last tank I filled up at 330 miles 16.45 gallons. mixed 50% hwy 20% city and 30% country roads through the pine ridge region of nebraska and i use super grade unleaded with 10% enthanol. ;)

I haven't looked to verify this, but when changing the air filter is it possible to contaminate or get dirty the airflow meter. If it is a hot wire type it maybe dirty and that could lower the mileage. Just a thought.


Just went out and looked...Didn't find an airflow meter in the RL intake piping or airbox. HMM, Guess that's not it.

If there was plastic wrapping on the filter did you get it all off?

This is prolly wrong but, I remember something about oxygenated gas and poor mileage at this time of the year.
TomJV