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Old 04-13-2008, 12:33 PM
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BNaylor BNaylor is offline
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Re: 1997 Buick LeSabre surging and tach problem

Welcome to AF.

Based on your symptoms your problem is consistent with a flaky crank position sensor (CKPS). Tach dropping off to zero rpms or no tach even though the engine runs is classic. Either bad 18X or 3X signal pulses from the crank position sensor since it is actually two sensors in one. The CKPS sensor provides the ignition timing for the engine and fuel injection system via the ignition control module (ICM) all controlled by the PowerTrain Control Module (PCM).

Also, it may not set a DTC so there may be no SES/CEL light (service engine soon or check engine light).



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