My 88 Iroc-Z will sometimes turn off while I am driving down the road at normal speed. Most of the time it will not give no signs or hesitate at all. But once it turns off I pull over and put it in park then and it cranks right back up. I only run 93 gas and i have put octane booster in it before as well but still will turn off. Does anyone have any ideas about what could be wrong?

Fuel pump could be on it's way out. Some give warnings and some just quit. Then again, with an intermittent problem like that, It's going to be hard to diagnose. Any codes?

We checked for codes the but it showed nothing except where I have headers

What do you mean "except where I have headers"

one was oxygen sensor