2001 Mazda B3000 bucking during acceleration

Just replaced the plugs, plug wires and coil on this 3.0 v6 and it still bucks and sputters during heavy acceleration or when trying to pass a vehicle on the open road. During normal driving or at a constant speed you rarely notice any problem. I have checked the egr valve and now am at a loss as to what may be causing the problem. Any one out here experience the same issue with their b3000?