2004 525i Poor MPG.
10-12-2010, 10:27 AM
#11
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My Ride: 2008 550I LOADED, all options except HUD and NV
Let's get back to the discusiion:
To the OP, try getting some new iridium spark plugs and replace the ones you have. I found NGK Iridiums for $6/ea at Kragen (O'Reilly).
Next, get a can of MAF sensor cleaner and use it. Luckily one of our members posted a DIY on how to clean it: MAF Cleaning
To the OP, try getting some new iridium spark plugs and replace the ones you have. I found NGK Iridiums for $6/ea at Kragen (O'Reilly).
Next, get a can of MAF sensor cleaner and use it. Luckily one of our members posted a DIY on how to clean it: MAF Cleaning
10-12-2010, 10:57 AM
#12
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My Ride: 2005 545i | Cold Weather Package | Premium Sound Package | Navigation System | Titanium Silver Metallic | Black Leather
Try cleaning your Fuel System with "Chevron Techron Fuel System Cleaner"!.. 
10-12-2010, 11:05 AM
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I'm experiencing some very poor gas mileage with my 2004 525i. Just for a quick overview the car has 86k miles and I've performed an oil change on it with full synthetic, has a K&N oil air filter that's brand new and has had the microfilters replaced as well. I reset the computer and took it for a very careful zen driving session to try and see what my MPG would be. As you can see it's a whoping 13.5 (air conditioner off)(tires checked and filled for proper pressure). It gets about 9-11MPG with careless fast driving.
I know for a fact this car has original spark plugs. Will it need a new O2 sensor? New spark plugs? What else do I need to look at to see what can improve the mileage? When I bought the car at 78k miles it was getting about 15-17MPG and now it's dropped severely, even with VERY careful driving. It has 20" rims on Nexen tires (TPMS goes off, but no worries all tires are fine, just bad sensor I need to replace after crushing it in an LA pothole).
It's worth mentioning that at idle if the AC runs it makes the engine quiet down, whereas if the AC is off the car rumbles more at idle. Any input would be appreciated, I'm getting tired of paying $200-250 a month in gas just to drive to work that is 15mins away.
I know for a fact this car has original spark plugs. Will it need a new O2 sensor? New spark plugs? What else do I need to look at to see what can improve the mileage? When I bought the car at 78k miles it was getting about 15-17MPG and now it's dropped severely, even with VERY careful driving. It has 20" rims on Nexen tires (TPMS goes off, but no worries all tires are fine, just bad sensor I need to replace after crushing it in an LA pothole).
It's worth mentioning that at idle if the AC runs it makes the engine quiet down, whereas if the AC is off the car rumbles more at idle. Any input would be appreciated, I'm getting tired of paying $200-250 a month in gas just to drive to work that is 15mins away.
10-12-2010, 11:07 AM
#14
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My Ride: 525i
I'll give this a try tomorrow on my day off, thanks for the suggestion.
10-12-2010, 11:07 AM
#15
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My Ride: 525i
Let's get back to the discusiion:
To the OP, try getting some new iridium spark plugs and replace the ones you have. I found NGK Iridiums for $6/ea at Kragen (O'Reilly).
Next, get a can of MAF sensor cleaner and use it. Luckily one of our members posted a DIY on how to clean it: MAF Cleaning
To the OP, try getting some new iridium spark plugs and replace the ones you have. I found NGK Iridiums for $6/ea at Kragen (O'Reilly).
Next, get a can of MAF sensor cleaner and use it. Luckily one of our members posted a DIY on how to clean it: MAF Cleaning
10-12-2010, 11:49 AM
#18
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Here's a DIY for cleaning the MAF:
https://5series.net/forums/topic/980...aning-diy-n52/
DOH!!! Nevermind, you don't have an N52...
10-12-2010, 02:50 PM
#19
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Here's a DIY for cleaning the MAF:
https://5series.net/forums/topic/980...aning-diy-n52/
DOH!!! Nevermind, you don't have an N52...
https://5series.net/forums/topic/980...aning-diy-n52/
DOH!!! Nevermind, you don't have an N52...
I know where it's at. Just can't wait to do it now..
10-12-2010, 03:10 PM
#20
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BTW, I just noticed the picture you posted showing the average speed of 16.7MPH. I wonder if that low speed for about 15 min. can be a factor. Were you always driving at that low speed when you first got your car? Also, I'm not sure about this but maybe the bad flat tire error could also be affecting the speed and MPG counter?
My car shows avg. about 17-19MPG at around 22MPH. My commute is mostly city streets. However, I've gone on long HWY trips on it and at one point even showed 33MPG.
I hope the MAF cleaning works out for you. Good Luck!
My car shows avg. about 17-19MPG at around 22MPH. My commute is mostly city streets. However, I've gone on long HWY trips on it and at one point even showed 33MPG.
I hope the MAF cleaning works out for you. Good Luck!