Yes I know this is yota tech but I got a buddy with a Nissan v6 hardbody that he ran 93 octane in it and now it is smoking with no power like a head gasket blew I'm not sure if the higher octane would hurt it any body got suggestions

 

I cant see higher octane causing an issue. I would run a compression test. The Nissan V6 is not a cheap motor to build or replace. I believe it is an interference motor, if timing gets out of whack that the valves and piston will contact each other. But since it is running that has not happened.

If I recall right, it is possible to get one tooth off on a Nissan motor on the cam and it will still run but will get hot after a while. Might see if there has been any motor work done lately and check to see if the messed with the timing belt.

 

It jumped time a while back and a guy replaced the timing belt but it won't run unless you hammer down real hard