2007 3.4 V6 pinging

My engine has developed a knock at highway speeds, the classic pinging noise. The temp seems fine (according to the gauge), I've run fuel cleaner additive through it twice (Techron), and I've been using higher octane gas. None of this has stopped the pinging. Is there anything else I need to do, look at, or replace?

If it has an egr valve, if not operating properly or the passages are clogged, this can cause what you describe.

A few more details. The pinging only occurs past 65mph or so, and will continue at those speeds even when coasting. When the outside temperature is cooler the knocking seems much less though, like early in the morning. Today we had a cold front go through, outside temp was only 50 degrees and knocked hardly at all. Checked coolant level and it seems full. Haven't checked the codes, but no check engine light.

If it is pinging when coasting this is not an ignition or egr issue.

Any other ideas?

Not without actually driving it.