What would cause a popping noise, and sluggish acceleration?

What is your question?

I just put new spark plugs, air filter, and wires on my truck. Ever since, my truck has been making a popping noise, and is very sluggish when accelerating to highway speed, Any ideas what could be causing this. I did find a vacuum line that the previous owner put a bolt in the end. I can't find where this is going to. Is this a possible reason for truck being sluggish? The previous owner said he did a tune up on the truck a couple of weeks before I bought it, in Feb of this year. Based on the condition of the plugs and wires, I don't thing so. The wires were of 2 different styles. Any help or suggestions would be appreciated.