The solution in this case would be just to adjust the rpm groundlevel a bit higher (e.g. from 800 -> 1000).

On most modern cars, the engine idle speed shouldn't be changed. It's often controlled by the electronic fuel injection computer, and it's important that it works properly so that the car can pass emissions tests.

He most likely has a problem with the car's charging system, a dead battery, or some sort of wiring problem.

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Tony Fabris