Something my 4Runner has done, just wanting to get an opinion, thanks in advance for the help.
For the most part, the engine runs great, but once in a while, pretty randomly, it will backfire. I don't have any idea what causes it, and I want to try to fix it before my truck dies on me.
Any advice will be appreciated.

 

is it a backfire: comes up the intake; or an afterfire: goes out the exhaust?

 

not really sure, i think it is a backfire. It pops, the RPMs go all the way to zero, and then instantly comes back, but the truck doesn't die.