Loud noise from engine area. Pinging?

While traveling about 67-70 mph or so on freeways, a loud banging sound which seems to come from the front right side of the car starts and stops at various times.

It almost sounds as if an object keeps hitting the car from underneath over and over but it's hard to determine exactly. It's very loud and sometimes happens every few seconds and then goes away but comes back at various intervals. I cannot replicate the sound through any routine. It always seems to happen at about this speed range as well.

I have noticed that it seems to happen when I am going straight ahead, not even changing lanes. It also seems to happen more often after I release my foot off the accelerator. Here's where it really gets weird...it seems to happen more frequently as I pass a vehicle on my right side. I almost always have my AC on if that helps.

Toyota could not find anything unusual from a visual inspection under the hood or underneath the vehicle but I haven't had the chance to ride with them yet so they can hear it.

This is not a mild sound, it is extremely loud and I don't have the best hearing. It has been going on for months and months.

Any ideas? Thanks.

 

Thanks. The first thing Toyota checked were the panels underneath the vehicle including those directly beneath the door and everything looked OK. What would cause them to start banging around when I wasn't even hitting a pebble in the road, just the wind?

This noise sounds more serious than that, it's very loud and sounds like it's coming from the right front side, maybe even the engine compartment itself.

 

Agreed. Of course, you know it will not happen then and he'll whip out his service notepad and jot down some powerful psychotropic meds for my perusal.