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Dan, Technician
Category: GMC
Satisfied Customers: 23972
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Databases
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GMC Yukon Denali XL: Read the question that you had online

Customer Question

Read the question that you had online about cold start rough idle on Yukon, I'm having the same issue.
Submitted: 2 years ago.
Category: GMC
Expert:  Dan replied 2 years ago.
Hello, my name is***** it idle fine when it warms up? Is the check engine light on? Thanks.
Customer: replied 2 years ago.
Once it starts for the first time of the day it's fine, if you hit the accelerator it stops running rough. Takes a full day after sitting at cold start before it will do it again. No codes or lights
Expert:  Dan replied 2 years ago.
It sounds like you may just have a dirty throttle body which can cause airflow restrictions at closed throttle conditions which will make vehicle idle rough. You can get some throttle body cleaner, spray it onto a rag, then wipe out throttle body good. Let me know how it goes or if you have more questions, thanks.
Customer: replied 2 years ago.
Just bought this a month ago and it's a certified GM car. Dealer has already replaced two injectors thinking it was bleeding down, also replaced plugs thinking they may have buid up. They say they tested the fuel pump and ruled that out. Never said anything about dirt throttle body.
Customer: replied 2 years ago.
You still there?
Expert:  Dan replied 2 years ago.
Hello, I am still here I didn't see you reply. Sometimes the throttle body can be so simple it is overlooked, it s definitely something I'd recommend trying especially since there is no check engine light. Let me know how it goes or if you have more questions. Thanks.
Customer: replied 1 year ago.
Have an appointment to do the rib service Monday, was wondering? It also has a rough idle when at a stop, plugs have been replaced and has no lights on.
Customer: replied 1 year ago.
Throttle body service
Expert:  Dan replied 1 year ago.
The throttle body service should take care of problem, let me know. Thanks!
Customer: replied 1 year ago.
Dan,The throttle body service was done and it still has a cold start issue. This morning on start up it idles down to the point where the truck seems like it may die out. Once the accelerator is pressed it straightens out and runs fine. When coming to a stop at a stop light it has a slight rough idle.
Expert:  Dan replied 1 year ago.
I'd check for vacuum leaks and if none are found replace the throttle body. Let me know how it goes, thanks.

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