i have a 1983 cadillac coupe deville and i have had two people look at my car and say i need a complete tune up. I have had the car for two years and think i am do for a tune up anyway. It has a ht4100 digital fuel injection engine. The question i have is what all do i need to replace and how much does a tune up usually run. And what else should i get checked.
At a minimum you want them to replace fluids, filters, plugs, wires, distributor cap and rotor, and then also have them degunk the valves from the top, clean your fuel injection system, etc. Ask them to check the timing, pressure test for leaks, etc. They may also need to replace stuff like valve cover gaskets and vacuum tubes.
Most of this stuff is no trouble but the plugs are hard to reach and the plug wires can be pretty expensive. Expect to spend a few hundred bucks for it. I dropped $900 on my last one, which included all of the above plus some minor repairs like vacuum tubes (this is excluding the actual repairs that I took it in for, which was another $600).
Don't buy the deluxe package with everything (timing belt, etc), unless you know you actually need it.