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International Automotive Technicians Network
Re: 08 Chevy Express-high idle/surging
Posted to Technical Discussion Forum on 8/13/2020

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Is the vacuum pump cracked/inop/leaking? That MAP is too high, which means vacuum is too low. Rule of thumb for MAP is 1/3 BARO at idle. (which is a neat rule, cuz "units" don't matter)

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