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International Automotive Technicians Network
Re: GM Nox/Negative Backpressure EGR Smog Failure
Posted to Technical Discussion Forum on 11/6/1999 3 Replies

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Hmmm... correct valve, adequate vacuum, and NOx improvment with a square holed potatoe stuffed up the tail pipe. Did you check exhaust back pressure? You should have 0-2 PSI off idle (~1500 RPM) at no... Login to read more.

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