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2003 gmc envoy_slt
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Discussion Starter · #1 · (Edited)
I have a 03 GMC Envoy with about 110,000 miles on it. I know the fan clutch is bad and its been ticking for a while. The motor just started knocking here lately. It will start up no problem and idle smooth as glass but it will knock and has no power. It almost seem like its holding its self back. The noise seems to be comeing from the topend. It was low on oil and I added to it and it seemed to quit it down some. The vehicle doesn't smoke or leak. Any Ideas? The check engine light was on but it went away when it started knocking.....go figure.
 

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2002 gmc envoy_slt
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Knock is a subjective term. It is a deep, thunk, thunk, thunk, kind of knock? A pre ignition kind of clattery knock? Or a tick, tick, tick, kind of knock? And yes...As Roadie has asked.....how low was the oil? What codes stored?

Over the years, I've found that the doctor's style of automotive stethoscope is pretty handy in these types of circumstances.

On an older chevy 350 I once thought I had a bad timing chain, after using the stethoscope, it turned out to be a rattling smog pump! HTH c good
 

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2003 gmc envoy_slt
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Discussion Starter · #4 ·
It was 2 quarts low and the code said something like exhaust valve-bank one opening to soon or something. I can really remember it.
 
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