Maybe some of you guys will find this useful....My Ford dealer finally fixed the pinging in my '01 5.4L. I had taken it in a couple of times complaining about the pinging and they always returned it with the invoice saying "problem not detected." Today, I took it in because it had developed a rough idle from cold start. This time they diagnosed it as having misfire data on cylinders #1 and #7. According to the invoice, they replaced the coil & boot assembly and the spark plug assembly on both cylinders. This seems to not only have fixed the rough cold idle but the pinging as well! The truck did not appear to have a misfire before but it does seem stronger now. It will be interesting to see if the gas milage goes up.

 

interesting post!! makes you wonder if those 2 cylinders have not been up to par for some time.