[twoheeldrive]

Try using Premium fuel. I know what the owners manual says, but the I-Force 4.7L V8 is a high compression 9.6:1 engine and really likes high octane (91 or better) fuel. Unless there is something really wrong with the engine or computer, pinging will stop and the engine will produce more power. Fuel economy should be slightly better too, which will help offset the higher cost.