2002 Ford Explorer lose wires

Engine Performance problem
2002 Ford Explorer V8 All Wheel Drive Automatic

i let a shadetree mechanic work on my car and now some of the clips on the wire going to the coils are broke and the same thing with the injectors and also if they arent broke they are not making a tight connection anymore. Can I buy these wires somewhere and if so what are they called. What would you do im at a loss. Thank you. Rodney E. Walton