Rough Idling when the vehicle is stopped

2007 CHEVROLET TAHOE

121,747 MILES • 5.3L • V8 • AUTOMATIC

BLKCROWNKING

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My truck has been idling rough whenever the vehicle is at a light or stop sign. I have a Vortec engine and I am wondering if that has anything to do with it.
I took the SUV to three different mechanics and they weren't able to find any issue. One of them even mentioned that they went through Chevrolet, and it was suggested that I find a similar model truck with the same mileage and run them side-by-side to see if the other does the same. I refuse to believe that this is the only way to test.
One mechanic even suggested buying a new Throttle Body. Rather than paying the $600.00 for the repair. I decided to clean the throttle body and the truck ran great but i still had some idling. I'm stuck and don't know where to go with this issue. I'm tired of having to pay for diagnostics without getting a solid answer.

Oct 24, 2019 at 11:11 AM

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KASEKENNY

AUTOMOTIVE REPAIR CONTRIBUTOR
18,907 POSTS

Hi,

You said it ran better after you did the throttle body service or did it just ran great but the rough idle did not change?

I attached a process called a throttle learn. We can do this without a scan tool but having one to monitor this data would be great if you happen to have one or have access to one. Specifically we want to see what the target idle is and what the actual idle is.

Not only do we want to see that the conditions are correct so that the ECM will learn the throttle but we want to see what these sensors are doing as one of them may be the issue.

I am assuming that there are no codes? Also, the shop that told you to compare it to another vehicle is telling you that because they suspect this is normal. Clearly I can't drive the vehicle to determine that but did this issue just start or has it gotten worse? Have you owned the vehicle a long time or did you just buy it?

Let's start with this and we can go from there. Thanks

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Oct 24, 2019 at 2:39 PM