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HELP! Bad gas mileage & KYB humming noise

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Old 01-11-2005, 12:53 PM
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HELP! Bad gas mileage & KYB humming noise

To All,

I was wondering if anyone can help me with some issues on my 2000 Maxima SE with 104K miles?

Issue 1) After installation of KYB GR2 shocks/struts (all 4 of them), the car makes this humming sound between 15-65mph. The car use to be quiet and cruise without any issues. Would these slightly stiffer shock make the noise?

Issue 2) The gas mileage has been horrible. I have been getting 21mpg on mostly highway. The annoying service engine light is on and when I had the code pulled, the reading says "Running Lean". I had changed the following items:
- Spark plugs at 75K
- Coolant at 80K
- Oil changed every 3K
- Air filter changed last week (which helped to shut off the Service Engine Soon light for about 5 days but the light is now back.

What else can I do to get better gas mileage?
- Change the automatic transmission fluid? If so, the local dealership is offering a drain and fill for $60 or flush and fill for $140, which one should I do?

Issue 3) When I release the gas pedal, the car slows down faster than before. Usually, the car would be able to coast more freely.

If you had any of these issues and have resolved them, please reply to my message. Thank you very much in advance.
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Old 01-11-2005, 01:56 PM
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Some of what you've done may end up correcting the gas mileage problem once the computer re-learns everything. I'd take the battery cable off overnight and see if it resets the puter.
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Old 01-11-2005, 02:48 PM
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If you've never done a flush and fill on the tranny, don't do it now. Stick with a drain and fill. Flushing it can remove the deposites causing it to actually fail. Once the tranny gets enough deposites built up, it basically fills in the gaps around the worn pieces. If the deposites are removed, sometimes the gaps cause the tranny to fail. I would also do what Klutch said and reset the computer. might help, but it really sounds like the beginnings of either a MAF problem or coil issue. The reason I'm leaning towards the MAF is because when you first changed the filter, the SES light went away. Guess what sits right behind the filter? The MAF.
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Old 01-12-2005, 06:48 AM
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Thanks guys for your replies. I will try disconnecting the battery tonight and see if that works. Also, I had the coils replaced around 90K. I am pretty handy so how hard would it be to change the MAF? How much are the parts and does anyone have instructions? Thanks again.
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Old 01-12-2005, 06:54 AM
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Originally Posted by Miata32
Thanks guys for your replies. I will try disconnecting the battery tonight and see if that works. Also, I had the coils replaced around 90K. I am pretty handy so how hard would it be to change the MAF? How much are the parts and does anyone have instructions? Thanks again.
I don't know about the MAF simplicity but I can GUARANTEE there is an FAQ on it somewhere on these forums.
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Old 04-07-2005, 01:36 PM
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Hello All,

Here are the solutions to all the problems with my Maxima.
Issue 1) After installation of KYB GR2 shocks/struts (all 4 of them), the car makes this humming sound between 15-65mph. The car use to be quiet and cruise without any issues. Would these slightly stiffer shock make the noise?
SOLUTION: One of the wheel bearings were bad and needed replacement. The front right one to be exact.

The other solutions for gas mileage was the MAF sensor unit. Stupid K&N filter released fabric like materials when it gets dry which caused the sensors in the body to go bad. This replacement helped to end the stalling in the morning. I also, cleaned out the throttle body which was really dirty with oil, replaced the PCV valve, and air filter.

The car runs smoother than ever and I did notice my steering wheel was more aligned then before. I would bet that the wheel bearing replacement assisted in this. I wonder if the bad wheel bearing was the cause of my front rotors going bad after 10k-15k miles?

Hope this post can help anyone.
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Old 04-15-2005, 08:45 PM
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so what's the typical gas mileage for highway for 03?
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