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« on: June 13 2009, 09:03:52 AM »
Stock V6's are balanced to allow the vibration to exit at the soft motor mount. When you build a fresh motor and have it rebalanced most shops use a formula (50%) that sets a vertical imbalance instead of the stock 36.6 horizontal. Not much you can do about this since you are trading off on up and down or side by side engine imbalance. The short answer is make the fueling a little richer at idle and open the plug gap. :rolleyes: Also check the basics like a vacuum leak, bad plug wires, worn plugs, bad maf and the other usual issues