Ok, I know the timing cannot be adjusted or maybe it can be? What parameters and things can the shops with those huge computers, change? Can they alter the fuel injection system in anyway? Or tune-it? Or maybe advance / retard the timing? What can they do using the computer? Here they charged me like $50 and said they adjusted the fuel injectors.. after they re-did the engine.. it was 'missing' and wasn't picking up nicely, but it was fine after they did that? I have some overheating issues, I want to take things out smartly so I'm just knowing more stuff.