[sbchevfreak]

Hey guys, Iv'e got a kinda wierd problem. 1990 F150, 5.0L, recent tune up, and this thing has a serious engine vibration, especially after it shifts into third gear. Almost feels like your driving over washboard. Timing is set to aftory 10*, spout disconnected. Plugs are good color, new wires, cap, rotor. Compression okay. You put it to the floor, get the revs up, it goes away, comes back when the revs go down. I'm just runnung out of places to look, any ideas?