Thought I had carb issues, but it was a loose battery cable?

Hey guys, I have a '96 with about 40k miles. I'm no mechanic, I just know how to turn a wrench. This year it has been running poorly, sounds like it is on 2 or 3 cylinders, had a hard time going over 7k rpm in 6th gear, etc... I thought I was experiencing some carb issues but, the other day I turned the key and lost all power to the dash. I charged the battery, but that didn't help. I disconnected the positive battery cable while I checked the fuses (which we all ok), reconnected the cable, dash power is back, and now it is running like a dream. Why would a loose positive battery cable cause it to run so poorly?

 

Loose connections do all sort of things to smooth running of a motor, you are running off the alternator causing pulses

 

Why ?? Really ?? Voltage is the answer. Why would a gerbil devour an oatmeal box ??