Hey guys, I've been getting a strange vibration around 80mph. It's not a consistent vibration, as in like a lawnmower. It's a vibration that shows up every 2 seconds, last for a half second to a full second, then stops. 2 seconds later, it starts again. I was initially thinking driveline, but...

Have vintage air on 69 camaro big block. Just installed FAST EZ-EFI and MSD 6AL ignition. Now when the engine is running with the vintage air controls in the off position. The fan turns itself on and off (intermittent) at different speeds for short periods of time.. Any ideas? Vintage Air tech...