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Discussion Starter #1
Hey guys I have an inline 5 2007 Colorado and lately at the first minute of initial start up, the truck seems to be bogging and cant seem to idle smoothly, but after a minute it seems to idle up to 1000 then goes to its initial idle at 700. I recently had a p0455 code which in turn I changed the Evap Solenoid module. I also got a new Gas Cap, and also just changed my spark plugs. Does anyone have any idea what else it could be causing this short rough idle at start up?
 

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perhaps the throttle body is getting dirty and this is the first sign.

Have you read about how to clean the throttle body?
 

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Discussion Starter #3
Not yet, but I will right away. Anything else that might be causing this? Perhaps a vaccum leak somewhere?
 

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Discussion Starter #4
Thanks for the suggestion! It was more than getting dirty, it was disgusting! lots of buildup! and noticed a huge difference with the power and idle after cleaning it!
 

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Nice job.

Most experience erratic idle when the TB gets really dirty. You didn't indicate such so I was thinking it was just getting to the point where it's time for service.

Glad it worked out for you.

Make a trip back to the parts store and get a can of MAF Sensor cleaner and give that thing a spray too. It may help with any residual rough idle if you still have any.
 

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Discussion Starter #6
Yah i noticed now that when I start the car idle goes up super high, then struggles to go back to normal idle..better than bogging out but still not normal..like you said it could be the MAF sensor..i need to get the tool to loosen it too...
 

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The MAF Sensor should be held in with two phillip screws, or s small socket?

A high idle could be a vacuum leak. Trace your steps to be sure you don't have a leak. Perhaps the o-ring isn't seated properly when you put it back in.

How did you clean the throttle body?
 

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Discussion Starter #8
Pulled it off the engine like how it was directed in the post on this site. cleaned it with the cleaner for it and put it back.ill check the hose thats connected to it to see if I installed it properly.
 

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Also the MAF sensor seems to use torx screws
I think the MAF Sensor screws changed over model year. I don't believe mine is torx...it's a 2008. I'd have to pop the hood to know for sure.

I wasn't implying you did the work incorrectly, however somethings things are overlooked on accident. Like the o-ring may have not been seated in the groove properly. Or there was a piece of crud on the mating surfaces preventing the surfaces to match smoothly. Just little stuff like that.

That PVC hose on the bottom/back may have come loose too, not sure if that will cause a vacuum leave scenario like you described.

If there are no vacuum leaks than the throttle body isn't being given the correct instruction in how to open the butterfly.
 

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Discussion Starter #11
I see, well I just cleaned the MAF and rechecked the Throttle Body again, will wait tomorrow to see what happens on a cold startup, if not I will let a mechanic check! Thanks again for your help. Im kinda seeing something suspicious with my fuel level too...Idk if I am just overly cautious. but ty again bro!
 
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