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2006 gmc envoy_slt_xl
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Discussion Starter · #1 ·
Hello everyone,
Tried searching this and found some close ones but not quite. Here's the issue. 2006 Envoy XL SLT L6.
Vehicle runs fine on cold startup however once the vehicle is a regular operating temp the voltage drops significantly when idling. Runs at about 550 rpm at idle however the volt meter drops from normally about 15-16 volts to about 11-12 at idle. now that it's winter here all the electronics go dim (interior lights & exterior) and the heater blower slows down. Was just back from the dealer and they said the code was for the MAP sensor which they replaced and said that it should correct the issue. No dice. :sadcry: Now a new code came up can't remember the number at the moment but it was Bank 1 running Lean (or something to that effect). I'll post the exact code when I do the work later this week when it gets warm enough to work on it.

I've read several threads showing items such as TB cleaning (which I'll do this weekend, no garage and it's -30C outside). I'll replace my air filter (I have a K&N but I hear mixed reports about the oil, MAF sensors etc.) I'm not a performance nut so I'd almost rather go safe unless someone can give me good reason to keep it.

Also will take it this weekend to get the battery checked but I can't see the battery causing the issue once it gets to a warmer temp. It starts fine, no hesitation or anything but again, correct me if I'm wrong.

Any help would be appreciated, I'll try to convince the dealership to determine the issue as they should have checked to see if the MAP sensor was the cause or a symptom of another issue. wish me luck. Thanks in advance everyone.

Dave
 

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2002 chevy trailblazer_lt_ext
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365 Posts
You should have the charging system checked. Most auto parts stores will do this for free. I would suspect the voltage regulator in the alternator has failed. That would explain why you have good voltage until things warm up.

As far as your lean code goes, clean the MAF sensor. There is a MAF sensor cleaner/spray available to do this. Most likely, the oil from the K&N has gummed up the elements in the sensor. When you clean/charge the filter, go easy on the oil. If you still get the code several miles later, check the sensor again for oil build up and you may have to switch to regular disposable filters.
 

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2006 gmc envoy_slt_xl
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Discussion Starter · #3 ·
update

Got up to 4C yesterday so it was warm enough to get some work done. cleaned the Thottle Body(TB) (surprising how dirty it gets after 100k). Used GUNK brand Intake Medic and it melted the dirt away. No scrubbing required the pressure of the can just blew away the grime. :thumbsup:

Replaced my air filter with just run of the mill paper filter. the K&N was really dirty... lots of oil in the bottom of the housing which means I may have been a little heavy on the trigger for the K&N oil. oops.:duh:

Also Cleaned the MAF sensor with SensorKleen. Used this before on one of my other vehicles and it did the job quite nicely.

Started it up and it runs fine. Idle speed is a little higher at about 600-650rpms now and surprisingly... no electrical issues. Drove around the city all day today (Christmas shopping) and never once did the voltage drop. My only hypothesis would be that the TB and MAF issue were causing a slightly lower RPM and the alternator need at least 600 to maintain full power.:undecided:

I'll see what happens in the coming weeks to see if it comes back again as an issue. For now :woot:
 
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