Pinging 99 Explorer Sport questions?

[aarong50]

My 99 explorer sport, which I bought this summer, has started to ping this winter. It pings upon initial startup (not idle) just a quick pinging noise as it turns over and is starting. It also pings at about 2500-3000rpm especially when under load like going up a hill.

The truck has 85k miles on it. I read there are a few possible recalls and if so do I fall in this category? Any and all help like always, its muchly appreciated.

 

[aarong50]

Anyone?

 

[Explorerhucker]

my 2000 was pinging.

I've replaced most everything and it comes and goes. People have told me to change my grade of gas to a higher octane which seems to help. Generally start by cleaning the MAF sensor and so on.
Good luck