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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29523
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 2005 trailblazer, new battery and at
, and new

Customer Question

Customer: I have a 2005 trailblazer, new battery and at
JA: Thanks. Can you give me any more details about your issue?
Customer: and new alternator it wont idle. it will start but when u take foot off the gas it will die
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Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

HI there, I am Cam. I suspect you have the issue where it idles up and down and eventually styles.

This is a common issue on the 4.2L engine. What happens is the system was likely reset because of the battery being remove. Then when it was hooked back up, the adaptations it had learned specifically for the throttle have been erased. It then idles differently when a load is put on such as the AC or rear window defogger. To correct this, take the upper intake plenum off, the black box that says 4.2L Vortec. There are 2 10mm bolts and 2 hose clamps. Then clean the throttle plates with a rag and carb cleaner. After that, take the battery cable off and reset the vehicle. This should fix this.