92 Sable V6 3.0 Random hesitation

Problem occured after I changed plugs and wires. Anyone have a Spark plug wiring diagram? Also cleaned out throttle body. Over 55 mph the problem doesn't exist. Under 55 mph the car will randomly hesitate. You have your foot on the gas and it starts to hesitate- step on the gas sligtly which results in little or no response. Then the problem goes away and comes back randomly. Any ideas?