I live by chamberlain high school,I had the car running this morning for like 30 minutes and had no smoke and no knock.When I got the car from cody it was in pefect running order besides the cooling system (bad waterpump and the coolant crossover bar was fised shut so I had to replace that.) everything else was fine,I'm thinking it might be a sensor since theoritically if something let go internaly it would knock all the time.