The tappet gap is typically measured with the camshafts still attached, unless they are hydraulic tappets. If they are hydraulic, there is no measurement because the oil pressure fills in the gaps. As for mileage gains, try doing a tune up. Spark plugs and wires(if equipped), filters, fuel induction service. Make sure your tires are always inflated properly.
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Friday, April 17th, 2015 AT 7:17 AM