Hey guys,

I recently purchased a 1985 Mitsubishi Mirage Turbo Hatchback and having been trying to fix it up but have ran into a couple particular problems that I don't have the knowledge to deal with. The first one is that the engine knocks under moderate to heavy acceleration. I put premium gas in it and have even put octane booster into the gas to see if that helps and it doesn't. I've been told it might be loose valves and have read that it may be a hot spot in the cylinder causing pre-ignition. The second problem is that under heavy load, generally at higher speeds, it loses power and the car shakes a lot and will cut out and studder a bit if I don't ease off on the gas. The more weight in the car the more this happens. I've already changed the fuel filter, plugs, wires, cap and rotor, and changed the oil since I've had it. If anyone has any ideas please let me know as I am about to just take it to a mechanic.