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2002 gmc envoy_slt
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11 Posts
Discussion Starter · #1 ·
My '02 Envoy has started bogging when you apply throttle at about 50mph in 4th gear. As you continue to press the throttle, the engine will drop in rpms until it finally decides to shift down to 3rd. Any ideas what could be causing this?
 

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2003 gmc envoy_slt
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7,190 Posts
Dirty throttle body, very dirty air filter, plugged fuel injector(s), need new plugs. More info would help. How many miles and what you've done or had done for maintenance.
 

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2002 gmc envoy_slt
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11 Posts
Discussion Starter · #3 ·
Sorry about the lack of info. The throttle body was cleaned at the local dealership recently, the latest programming was also downloaded and it seems to run okay at idle, although it will bog down when the a/c compressor cuts on and the compressor will immediately turn off. It has 93k miles and the air filter is clean. After posting, I read a few posts about the symptoms of a clogged converter and am leaning towards that being my issue. I will probably replace my plugs soon but if they're like the ones in my old Trailblazer they probably aren't really needed.
 

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Northwest Chapter
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11,824 Posts
Guaranteed the dealer didnt clean the throttle body like everyone here recommends. They spray some cleaner on the front and call it good, you need to pull it off and clean the backside where buildup occurs. Takes like 30-60mins the first time and even if you have 0 mechanical experience, if you can unbolt the battery negative cable and remove like 8 other bolts you can do it.
 

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2002 gmc envoy_slt
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11 Posts
Discussion Starter · #5 ·
Thanks for the advice. I'll give it a shot this weekend along with changing the plugs.
 

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2004 chevy trailblazer_lt
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13 Posts
I had a blocked cat and the truck was gutless and would shift up too soon.
You would really have to step on it to get a shift down and speed up.

The mechanic disconnected the exhaust and took it for a short ride. Right away it was obvious that it was blocked. Do a search for hair like stuff in exaust.
 
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