One of my injectors is blocked, and the fuel economy is poorer than it should be. Mileage 192,000 miles FSH. Injector cleaner has made little to no difference. Its cheaper to buy recon injectors than have mine re-conned Work that out. Last time I had the top off, it all looked clean and neat in there - no seal blowby as far as I can see. Is this reasonably DIY-able? Claw spanners, torque wrench etc in my kit.