At 158k miles, I would think the motor is probably had at least several mechanics work on it. The history of the repairs and an actual read out of a smooth running test (the same piece of equipment used at the dealer to extract codes) done during the time when the fault is occuring would be my path to diagnose. It sounds like a misfire or loss of compression in one or more cylinders and the smooth running test will tell which cylinders are at risk.
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Monday, March 1st, 2010 AT 10:25 AM