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MAF/Injector Scaling - Hunting Idle and Sporatic Spark Advance

Practical Reflash Tuning

Discussion and questions related to the course Reflashing


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I may be jumping the gun here, but is it common for a stock car to have the idle RPM hunt like that from 520 to 580 RPM as well as such a sporatic spark timing ranging from 8 to 17 degrees? I'm asking because I am witnessing similar behavior on my 2001 GMC Sierra 4.8L 4L60e engine swap in very stockish form, less EGR, Cats, Air Pump.

Yes that's totally normal. The ignition timing is used to help control the idle speed and as such it will jump around significantly in order to control engine torque.

Thank you so much Andre I really appreciate the super fast reply. I have spent money on MAF cleaning chemicals as well as Throttle Body cleaning chemicals, but oh well it didn't hurt to clean them, glad my engine is idling as it should.