Im driving down the street everything feels fine car runs awesome then all of a sudden the tachometer stops working and the power gauge starts acting funky and the car starts stumbling and coughing then all of sudden everything goes back to normal(tach works, cars feels great). It did this(back and forth) all the way back home. I dont know what the hells going on. I thought maybe its something to do with the msd ignition wiring but i dont know. Also im using an msd blaster2 coil instead of using the msd gm coil.(im going to switch the coil out this weekend)

 

Sounds like aliens to me. Check to make sure you dont have any loose connections at the msd box, battery, or alternater.