More on the wife's '99 Ranger I mentioned earlier. Hers also pings some only when going up on either of the overpasses here in town. I found on the internet thats normal for these 3.0 pickups with the FFV engines. The engines are also designed to burn ethanol. One fellow replaced all his injectors and it helped very little. Another replaced two injectors that Ford said was bad. Still he had some ping under heavy throttle.

My wife gets great gas mileage with her pickup. She bought it used and it does have the larger tires on it. Being a automatic with overdrive, she drives 45 miles per hour the 8 miles to town. She gets 26 to 28 mpg with the AC on. She runs it on low fan. She did go to the mid octane fuel and that eliminated the ping and she picked up a some gas mileage. We use 5W-20 mobil one in that one. The pickup had 18,500 on the clock when we bought it from the Ford dealer. Its now 5 years old with 30K on the meter. She don't drive it that much.

She also uses top tier gasolines, was Chevron but these last few years seems that Phillips 66 may be a little better. I have had good mpg results using Phillips in the TCH. Conoco and 76 should be the same gasoline.