Yeah I agree with "Jack", it wouldnt hurt anything to replace your distributor cap and plugs, you may not necessarily need to change your wires though. A major tune up in that department could run you up to 500.00(in CA.) I'd reccomend buying the Haynes book of repair on the 93 850 and do it yourself. You will save a butt load of money and if you follow the steps and use the right tools you'll find that its fairly easy and can be done in an afternoon.