Ethenol Causing Rough Idle?

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01-19-2009, 03:47 PM

Hit The Road Jack

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Ethenol Causing Rough Idle?

2004 Mazda3...5 door...55k on OD

Anyone else experiencing this?

01-19-2009, 05:31 PM

virgin1

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Location: Manor, TX (Outside of Austin)

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RE: Ethanol Causing Rough Idle?

Ethanol, at least a <10% mix, should able to be compensated for by the ECU/PCM? If you are experiencing a rough idle my guess is that something else is wrong.
It could be a MAF that"s not happy, or a evap fuel valve solenoid that"s stuck open. These are two pretty common problems.
You might try cleaning the MAF first. Be careful to be gentle with it as it"s a rather sensitive piece. CRC offers a MAF sensor cleaner at your local parts store.
You might also try resetting the ECU afterward by disconnecting the battery for +/-10-30mins.

It just occurred to me as I was wrapping up this post, but how are your motor mounts... especially the upper, "fluid filled"one on the passenger side. A bad mount can also make the car seem to have a bad idle when it"s actually normal.

01-20-2009, 05:49 AM

Hit The Road Jack

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Join Date: Aug 2007

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RE: Ethanol Causing Rough Idle?

Thank you virgin1

The motor mounts could have been disrupted from one of the 2(light) rear endings we've experienced.

IMHO, ethanol is not a 'good thing'

Jack

01-20-2009, 03:57 PM

virgin1

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Location: Manor, TX (Outside of Austin)

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RE: Ethanol Causing Rough Idle?

That one in particular seems sensitive to dry rot and losing it"s fluid. They"re about $70 from Mazda but there are a few available on the AM too.
And I agree. Ethanol is not my favorite thing to run in my street car either. For one thing, fuel mileage is reduced, but the cost is not.