Got this error [ Expected identifier when parsing expression, got 'for'] can anyone help me fix it?

local run = false

while wait() do

if run == true then 
    return

for i= 1, 300 do
    script.Parent.CFrame = script.Parent.CFrame * CFrame.new(0,0,2)
    wait()
    end

for i= 1, 300 do
    script.Parent.CFrame = script.Parent.CFrame * CFrame.new(0,0,-2)
    wait()
    wait(2)
    end

    script.Parent.CFrame = game.Workspace.SubPos1.CFrame
    run = true

This is a script for a car that goes down a track, i'm trying to make it to where when it reaches 'run = true' at the bottom that it repeats the action again.