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Cadillac
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Discussion Starter #1
Hey guys,

I recently purchased a used '97 Deville Concours and the car has started to make a knocking/fluttering noise when accelerating. It typically only happens when I am accelerating lightly - if I floor it the noise is reduced/non-existent. It doesn't seem too serious, I figured it may be suspension problems or something loose in the engine, but Im not sure. Any ideas on what could be wrong?

JD
 

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White Diamond '03 DHS (with DTS floor shift)
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86,994 Posts
Hard to tell from that description. Metallic sound? Exhaust sound? Spark knock? Got any codes?
 

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06' DTS
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65 Posts
I have the same thing...

Do you have alot of miles on the motor... ? I've got 199,000 miles and mines been doing it for about 30,000 miles. Seems to do it whane the motor is hot, also only under light throttle..

I thought it was piston slap but it does it when the engines hotter. Also it very well could be a lean detanation condition. you and I should noth try this. Uuplug the MAF wire. It's the round plastic piece just beofe the throttle body. by doing so your causing the engine to run in speed density mode, which is fine. Try then your light throttle, if the knock is gone it could be a maf failure..

It's worth a try.

Clint
 

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2008 SRX
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403 Posts
Check the exhaust pipe for grounding out just behind the cat. Depending on the clearance (or lack thereof), this can cause a grind or growl that varies with engine load.
 
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