1998 Nissan Maxima a dull sounding hum

1998 NISSAN MAXIMA
140,000 MILES • V8 • 2WD • AUTOMATIC
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TYLERROCKARD
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my engine is running fine appears to have no problems but for the fact after i have driven a realativley minimal distance whenever i have to decelerate abruptly (such as for a stop light or stop sign or to make a sharp decrease in speed to make a turn ). there is a sort of dull pulsing humming sound that disappears as soon as i again accelerate
Apr 11, 2009 at 4:51 PM
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JAMES W.
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Does it make the noise only in a turn, or also when stopping straight on? Please advise.
Apr 11, 2009 at 7:56 PM
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TYLERROCKARD
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the pulsating humming noise is directly related to the abrupt decrease in speed when either stopping straight on (( such as stop light or stop sign)),or having to sharply decrease speed to make a turn ,, there is no noise apparent at any other time while driving or when increasing speed,,,, and when the pulse like hum does occur ,, it disappears as soon as speed is accelerated again
Apr 12, 2009 at 6:50 AM
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JAMES W.
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The only thing I can think of that would make the noise you describe, at the times you say, would be the "air injection pump". This pump is part of your emissions control system. It is designed to inject fresh air into the exhaust system on deceleration to reduce hyrocarbon emissions.
If the air pump is going bad, it will make noise when it is activated on deceleration. I could be all wet here, but this is the only thing that makes any sense. You may want to have this checked out.
Apr 12, 2009 at 5:42 PM