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Old 12-30-2008, 07:30 PM   #6 (permalink)
Wannabe greenie
Join Date: Aug 2008
Location: Yorba Linda, CA
Posts: 1,098

The Clunker (retired) - '90 Honda Accord EX sedan
Team Honda
90 day: 29.49 mpg (US)

Mountain Goat - '96 Ford Ranger XLT 4x4 SuperCab
90 day: 18 mpg (US)

Zippy - '10 Kymco Agility 125
90 day: 65.03 mpg (US)
Thanks: 5
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I think cold is a factor because the engine is actually working that much harder. On my Honda, my normal idle is 21-22, but when I start the engine on a cold morning (<32 degrees), it's 16-17, and then when I let the clutch out in neutral, the extra drag of the cold transmission lube drops the idle to 14-15. Also, higher altitudes seem to reduce vacuum as well, probably because the engine needs to work harder to get the same amount of oxygen in.

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