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Average MPG??

9K views 58 replies 26 participants last post by  peytonracer4 
#1 ·
Hi everyone,

My MPG has been lurking around 18.8 and used to be at least 20! What could be causing this? Checked my tire pressure and have some idle issues which should be fixed once I clean my ICV? Any idea how I can get it Back up to i guess normal which should be around 25mpg? Thanks
 
#8 · (Edited)
I was getting 22 hwy/city mile, and that was before I found the oil leak and changed out the oe spark plugs and Valve cover (oil on the plugs). I also cleaned the ICV and TB. Hope mine goes up, we'll find out this week.

When you clean your ICV take the time to clean your Throttle body also. After your ICV is out, its only four bolts, and an electronic clip. The front of mine was not bad, but the back side was covered in grime to the point it was restricting movement. There is a orange rubber gasket on the back, make sure that is in good shape also.
 
#11 ·
119k 323ci 5 speed. 28 town / 34-35 highway. Maintenance is up to date and just replaced my fuel filter which gave me an extra 1.5 all around.

These are my average numbers to be honest, even with some spirited driving and high shifts.
 
#12 ·
Well.. Depends on whether we're talking about the OBC display or calculated based on miles and fuel fills.. The OBC usually over-predicts by 2-3 mpg.. Calculated, I used to get around 21-22 mpg city, 30-31 mpg hwy and around 23-24 mixed... A little more in the summer, a little less in the winter. '04 325i with 5-speed manual and around 80k..
 
#17 ·
Driving like a tank is not good, imo (for as little as it counts) it seems like your not getting enough of something: spark, gas, air (those are the easy ones to check). Make a check list, and take your time, also, check your codes anyways. My light doesn't come on, but it will still store codes. I just figured my light is burnt out.

also Edz, how long has this been going on?
 
#19 ·
<<<<<<<<<<<<<<<<< comfortably gets 36mpg
 
#25 ·
I have a K&N in my camaro, so I won't bash them too hard, but they are notorious for aiding to the build up of gunk on the intake parts. In your case, MAF, ICV, and Throttle body. As a few of us said on the first page, start with cleaning those items really well. Cleaner is decently cheap, and it's a better starting point than throwing parts at it :p. Good Luck, keep us posted.
 
#27 ·
I'm gonna take It apart this weekend and check out the icv and clean the throttle, any special sprayer I should use? Throttle cleaner spray works fine? Also I know what you mean about k&ns I love em and hate em, but it's sucha huge difference compared to stock filters!
 
#33 ·
I get between 23-26 driving around town. Last year I drove from Denver to Tulsa, averaging 31-33 with 4 guys in the car, cruise control at 80 mph. Verified with OBC and the old fashioned way.

This weekend I replaced a horribly cracked lower intake boot causing my MPG to drop from my 25-26 avg to 23-24, does anyone know if this is just the MAF adjusting for the long period of a bad lower intake boot? You could stick your pinky thru this thing. Oh and the "whistle" problem was fixed with this repair...
 
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