tune up/when??

[Mr 5 0]

I use a standard Motorcraft filter and change both oil and filter @ 2,000 miles. Recommended.

I would definitely change the oil & filter. Then check, clean & re-gap the plugs, check and clean off the wires, check the wear on the cap & rotor (they can corrode from age). You'll probably want to replace the rotor and look hard at the cap's terminal contacts. Replace the cap if needed. Check the PCV (should be fine) replace the gas filter @ 15,000 miles. Wash and re-oil the K&N air filter. Check the timing and the TPS voltage, too.

Be sensible but faithful about mainteinance and your Mustang (or any other car) will usually reward you with good running and less breakage.