Have you simply had the engine on a scope that will tell you if it is getting the proper advance throughout the rpm range? I truly don't mean to be a wise guy, but the most common cause of pinging is too much advance at a RPM, temperature, elevation & load combination! "When you hear hoof beats look for horses before you look for unicorns!"

If you've done that, "sorry" & ignore my post!

 

what is this magical "scope" you speak of ??

 

Nothing magical! They have had testing equipment since the '50's that could tell you how much "spark advance" you are getting at different RPM's! In Ancient times we changed springs & weights to give more or less advance in an old mechanical distributor! Check with a good speed, tune up, or Mustang shop to see if the advance is correct! Good luck!

 

Have you tried running a couple tanks of premium fuel thru it to see if the pinging goes away.

 

what I think about premium gas...

 

uh ok. Premium fuel allows you to run a more advanced timing without pinging, due to early detonation. If you have a timing issue, the premium fuel will eliminate the pinging. If it doesnt, then you have a different problem other than timing or you dont have pinging.

 

so if it is a timing issue, how do I fix it?

 

crank position sensor, cam position sensor or tune.

 

+1 on the premium fuel for a try, 99-00s occasionally have the problem, $0.20 a gallon for 15 gallons a tank is $3 per tank.... Cheaper to try that then throwing parts at it

 

look on the shock tower, there may be an octane bar that you can unhook to reduce timing and stop the pinging, yours may or may not have one

you can clean carbon out by getting the engine up to operating temp and sucking water through a small vac line, that will steam clean the pistons and might potentially help with detonation

most likely its over advanced in that light load/rpm range, youd need a programmer to get in the ecu and fix it correctly

you can download the free custom tuning software for the 99-04 fords on my website including a base tune for the v6

http://info.efidynotuning.com/fbfg2.htm