Spitting and slight missing

I've got a b350 86 van Intermitently I get a slight missing on the freway. Going up a hilly driveway I got a bout three big spits. Almost like the engine was sneezing. The fuel pump was replaced back in Dec of last year. I recently put on new plug wires. I bought the mid grade wires about $45 I think. I am guessing I didn't get one of the wires on with a good connection. What do any of you guys think it might be?
sCary

My bad. I didn't get one of the plug wires on very well. Got that taken care of and now she purrrs like a kitten. During that period that the wire was lose. I got 7 mpg. I real curious noe to see what I get.
I have a 15 passenger van with the 360 motor.