My 01 gt has a vibration/ engine issue that I can't figure out. The car is pretty much stock except for billet steel flywheel and stage 2 exedy clutch That were installed 2 months ago. I noticed this issue a few weeks ago on a 300 mile trip. It seemed as though the car had an intermittent miss at 60mph+. The car will jump if too much throttle is applied. I thought it may need a tune-up, so I replaced the plugs with autolite 764 copper plugs gapped @ .054. I also cleaned the maf w/o removing the sensor from the housing. And i replaced the fuel filter. Most of the problem was gone, for about a week. Slowly the issue got worse again. I changed all the coil boots, no change. I borrowed one of my friends accel coils and swapped it into every cylinder with no change. The only cel code it has is for the idle air control valve excessive flow. Please help with some advice on where to look. I can tell the engine exhaust does not sound right.