I have terrible "pinging" (spark knock) problems when driving my expy. Have replaced everything that could possibly cause the problem...am I missing something? I have read that ESC (electronic spark control) on some vehicles takes care of this, but did Ford use this in the Expeditions? Particularly the 97's? I have tried mid grade as well as hi octane gas...I have tried numerous fuel system cleaners...I have had the fuel injectors checked......there has got to be something I am missing. Any suggestions would be quite helpful.

 

Your pinging is most likely caused by a defective DPFE sensor. I have had them go bad in 3 F150s/Expeditions and they always caused a pinging. While you're in there, pull the EGR valve, clean it, lube it and reinstall it.