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George H.
George H., ASE MasterTechnician
Category: GMC
Satisfied Customers: 18595
Experience:  15+ Years ASE Master Technician with Level 1 Certification
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How is the base idle adjusted on a 1993 GMC suburban K1500?

Customer Question

how is the base idle adjusted on a 1993 GMC suburban K1500?
Submitted: 1 year ago.
Category: GMC
Expert:  George H. replied 1 year ago.

Hello I will help you with your question,

Minimum idle is controlled by the computer using the idle air control valve and is not adjustable. If it is high you have a vacuum leak.

Please let me know how I can help you with your question

Thank you

Customer: replied 1 year ago.
my engine idles too low when stopped at traffic lights, etc. Occasionally, it will cut off. When in park or neutral it revs up. I have
replaced several IACs with no relief. What now?
Expert:  George H. replied 1 year ago.

You will need to see what the computer sees. With no adjustment available for minimun air then you know the computer is not getting the correct information.

Cleaning the intake tract, throttle body and checking EGR operation might get you some relief but the key is watching what the computer is using for input and judging if it's commanded outputs are being followed so that requires a good scantool and diagnostic equipment and time.

I hope you understand my answer to your question about the adjustment of minimum idle speed, there is no adjustment available.

Thank you