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2005 gmc envoy_slt
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Discussion Starter · #1 ·
Let me start by saying what a great forum this is. I just came across it yesterday. What a knowledgable group. I'm hoping you can give me some ideas of what to try on a problem I'm having.

I have been ignoring a fuel system related problem on my Envoy that has seemed rare and relatively harmless for about the last year. It happened yesterday morning though in a freeway on-ramp situation that wasn't pretty. Looks like it's time to get off my rear end and fix the problem.

The truck has about 85K on it now. No other performance issues. MPG doesn't seem to be affected. It first happened on a road trip on a tank of gas I got from a suspect station in a town where I had little choice of stations. Since then I've run many, many tanks of good fuel through it. I tried the water absorbing additives but that obviously wasn't the problem. It normally happens when the tank gets low or rarely soon after I have filled the tank. Most often it is after the vehicle has set overnight and the engine isn't up to temp, but not always. It always starts right away though. Even after it dies at a stop light. I will notice hesitation on accelleration shortly after leaving my home. The engine will idle roughly at a stop and sometimes even die. Normally idle is smooth and rock stable. This mild stumbling and poor accelleration usually only lasts 5 to 10 seconds and then the engine takes off and runs smooth as can be. I would have replaced the fuel filter but I have a 2005 with the "non-serviceable" filter in the fuel tank. Any ideas on what the cause of this behavior is? Thanks!
 

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2004 gmc envoy_slt_xl
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134 Posts
damn i also got the same issue. Ill be having my Envoy oil change tomorrow, i will also tell them to clean the throttle body. I got m envoy from toyota dealer.. i am just wondering if they do the same service as GM dealer? Thats what I will ask them tomorrow.
 

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2004 gmc
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26,181 Posts
If you're not going to do it yourself, at least discuss with the mechanic that it's a subtle issue that affects our vehicles, and involves the "adaptive" process of the PCM learning the behavior of the throttle body. The battery has to be disconnected, and the throttle body removed to totally clean the BACKSIDE of the throat. A simple spray in the front won't do. And disconnecting the battery for the duration of the process is mandatory. And they have to use "sensor safe" throttle body cleaner, not old-fashioned carb spray.
 

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2005 chevy trailblazer_ls
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1 Posts
I am having the same problem with my '05. I cleaned the throttle body and it didn't seem to help much. Also changed the air filter. Truck has 60K on the clock and its driving me nuts!!!!!! :crazy:
 

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2002 chevy trailblazer_ltz
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3,250 Posts
I am having the same problem with my '05. I cleaned the throttle body and it didn't seem to help much. Also changed the air filter. Truck has 60K on the clock and its driving me nuts!!!!!! :crazy:
You removed the throttle body from the engine, and cleaned front & back sides? You had the battery disconnected the whole time?
 

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2005 gmc envoy_slt_xl
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Same issue here

I have the same rough idle issue associated with an intermittent SES light that describes the issue as a camshaft position sensor. A mechanic looked at the compression and found cylinder #3 to be about a 1/3 of the other cylinders which he thinks is throwing the erroneous error. He wants to do a valve/piston job or replace the engine. Is this engine prone to these sorts of issues? I've cleaned the throttle body and replaced both the camshaft position sensor and solenoid. Any other ideas?
 

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2004 gmc envoy_sle
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Awsome Forum

I bought a used 2004 GMC Envoy, I had the same problem, when i would use the a/c or the heater.. the truck would loop idil and then die. I took it to the dealership, THEY COULD FIND ANYTHING WRONG WITH IT... they had it for 3 weeks, then finally tell me "sorry we cant help you". So i get on this forum, clean my throttle body and wham, it runs better, stronger smoother... its like driving a whole new truck.... Thanks everyone, your a live saverhttp://forums.trailvoy.com/images/smilies/woot.gif
 

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2005 chevy trailblazer_lt
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Intermittent rough idle, intermittent check engine light

OK, like so many others on this post, I have an 05 TB with about 63K miles. It idles rough, but not all the time. I cant find a correlating factor (like the AC, or pushing on the brake pedal). I disconnected the battery and cleaned my throttle body (which was dirty) and I still have the same problem. Any ideas?
:bonk:
 

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2004 gmc
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26,181 Posts
Try a Seafoam treatment, then change plugs. Other ideas posted in similar threads include a camshaft position solenoid problem, fuel filter (I don't see this doing anything at idle), air filter, cleaning injectors, marginal coil packs, and a dozen less likely issues. Many of those would throw a code, so if you never see a SES light, they're probably not your root cause.
 
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