RPM's dropping when I hit a hard bump?
 

I have a 2005 4runner sport v8, 105,00 miles and I've been having a very intermittent problem with the truck stalling. A few times I've come to a bumpy stop light and the truck died out, first I chalked it up to putting 87 octane in during hurricane sandy but then it happened months later with a full tank of 91 in it.

Over the weekend I seafoamed, replaced the plugs, cleaned the maf and tightened down the battery tray/cleaned the terminals and it still stalled, when I'm coasting on the highway and hit a big bump I can see the rpms drop from ~1,000 to 400-500 for a second then they jump back up...I'm assuming that's my stall when I'm going under 5 mph and hit a hole. Any suggestions?

If it does it on bumps I would guess a loose electrical connection or ground. I have had a bad battery with a short in it do the same.

....or a loose vacuum hose.