Hi sorry for the late reply. Car is the early AGU variant. K04 turbo upgrade was running 270bhp for about 10k miles until misfire. Yep I changes ignition amp and plugs the first things I tried. Vagcom scan doesn't bring up any fault codes. I think I need to find someone to test the ignition system.....

Hi there, I have a Golf mk4 1.8T with a 'high boost' misfire. Above 10psi the car will produse a high frequency misfire, throwing out back smoke / unburned fuel from the exhasut. All 4 plugs are sooty from the misfire. I've interchanged the following parts with no improvement:- MAF, Lambda, Fuel pum...