Changed out the intake manifold gaskets on my '94 z28, and now the car shudders at all rpm's and real bad at 4,500rpm+. Found #3 plug wire was arcing, changed out all the plugs and wires and it still shudders. At night you can see blue arcing down by the distrubutor at the coil wire. There is some arcing near the coil too. The coil wire has been changed out 2 times this week, and the opti was changed out a couple of days ago too, along with the coil. Still does it... Running out of ideas. Strange this started after a gasket change. EGR, MAP, fuel filter and oxygen sensors are all new too. Any help will be appreciated! Thanks!