S2000 Under The Hood S2000 Technical and Mechanical discussions.

Horrible MPG..

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Old Apr 25, 2014 | 11:04 PM
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Default Horrible MPG..

I have been averaging 20 mpg on MY06 with about 80% city and 20% highway, but recently I've been getting about 15 mpg. My last tank I got 150 miles before the gas light came on. I've seen people get 30-60 miles on a full tank before losing a bar on the gas gauge. I've started losing a bar after only going 7 miles.. I've recently tried changing my gas cap, resetting my ecu, and checking tire pressure. Any other idea on what might be causing the drop in gas mileage? Thanks
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Old Apr 25, 2014 | 11:37 PM
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I average 210 on a full tank. I daily my car and drive up through the canyons once or twice a week. Is your alignment on point? When I bought new tires (OEM spec) my mpg tanked. A full tank (that normally lasted 7 days) would only last 3-4 days. After I aligned the car everything was back to normal.

edit: also, I don't know what kind of black magic goes on in our gas tank but once I get the gas light I could anywhere from 0-4 bars at any given time.
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Old Apr 26, 2014 | 03:32 AM
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I have no idea but thats pretty bad mpg granted I drive mostly highway but i average 31mpg.
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Old Apr 26, 2014 | 04:46 AM
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check fuel filter, all injectors, fuel line, process of elimination which is a major ball-ache but in the end you'll find the cause, hope all goes well.
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Old Apr 26, 2014 | 06:51 AM
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Check for a dragging brake... a jammed slider pin can leave you with no full release.
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Old Apr 26, 2014 | 09:03 AM
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I used to get bad mpgs and low power on the stock ecu for whatever reason. The ecu was pulling timing for an unknown reason. I swapped to Kpro, got a custom tune and it all literally went away. Maybe a bad knock sensor, throwing false alarms at the ecu?
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Old Apr 26, 2014 | 09:26 AM
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Originally Posted by cdelena
Check for a dragging brake... a jammed slider pin can leave you with no full release.
You said full release lol
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Old Apr 26, 2014 | 09:30 AM
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bad o2 sensor?
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Old Apr 26, 2014 | 09:30 AM
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Process of elimination for sure. I have an 06 and have noticed that after changing the throttle position module, I lost about 1 days commute in fuel. It likely needs calibration or something... I recently replaced plugs, filter and had alignment done. I do need tired so that could be a contributing factor also.
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Old Apr 26, 2014 | 09:47 AM
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Originally Posted by fullleather
check fuel filter, all injectors, fuel line, process of elimination which is a major ball-ache but in the end you'll find the cause, hope all goes well.
I checked for fuel leaks under the car and in the engine bay no leaks or fuel smell.

Originally Posted by cdelena
Check for a dragging brake... a jammed slider pin can leave you with no full release.
I just checked and all the wheels spin freely.

My intake air filter looks dirty so i'm changing that next and will see if it makes a difference.
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