I have a 2000 f150 4.6 and i can not get it to stop pinging. It does it when it gets hot or underload. Tried high octane fuel but no success.

 

How long have your plugs been in? miles/years?

 

Do a BG induction. Excessive carbon in the intake valves will cause this condition. I am a HUGE fan of that stuff. I have seen it work wonders. BTW My wifes truck was doing the EXACT same thing. I didn't know about it until I rode with her one day. I was like WTF is that clatter? She was like "oh its just the valves its been doint that for months: ...:O Did a BG and the problem was gone.

 

This has been going on since the truck had 40,000km on it. It now has 110,000km. I replaced the plugs at 90,000km. I gets worse with the warm wheather. I also tried a K&N

 

Have you cleaned your MAF?

 

cleaned maf, replaced air temp sensor,cleaned injectors,. I wanted to know is it possible to get a different program for the pcm or have a dealer reflash it?

 

With all that you have done I would say you have excessive carbon build up on your valves and suggest like NGM said go with BG industries products for cleaning. I don't think you have a PCM problem.