Keep it factory baby!
Ok guys i need some serious help. I have an 06 2.4ltr G6. 73k. I change the oil like clockwork, air filter is good, new tires, fresh spark plugs (AC Delco) and i am getting bad gas mileage. Why? Whats gonna help? The dealership did a full cleaning of the fuel lines and injectors not quite a year ago. After they did that, gas mileage was great for a few weeks and now im back to square one. No check engine light has been on. What am i missing?