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Old 07-25-2012, 03:51 PM   #6 (permalink)
Ryland
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Join Date: Jan 2008
Location: Western Wisconsin
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honda cb125 - '74 Honda CB 125 S1
90 day: 79.71 mpg (US)

green wedge - '81 Commuter Vehicles Inc. Commuti-Car

Blue VX - '93 Honda Civic VX
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A common pattern for the hesitation is bad o2 sensor, unplug it to test it, if the problem goes away then it's the o2 sensor, while it's unplugged it's running in open loop mode and will be running a bit richer and will never go in to lean burn.
Other problem that can cause hesitation is a bad throttle position sensor, but that is much less common.

Common problem that causes idle bounce is a vacuum leak, check the PCV system including the lowest point in the hose, under the intake manifold, there is a grommet that drys out and shrinks causing a vacuum leak, $3 part and someone with small hands tends to take care of it.
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