My '03 ran more than a bit rough at 130,000.
From drive to park it would idle down and
almost die. It also missed occasionally at idle. Mileage was down, but still not to bad.
I decided the plugs needed changed....Changed plugs & wires on 4, 5 & 6 without to
much difficulty but 1, 2, & 3 kicked my azz.
Gave up and went to Ford and had them change 1,2&3 for 130$...I supplied the plugs and wires. You can DIY for about $60+ or have it done for about $260 + parts.
Runs much, much better now. It was probably way past time for new ones....the platinum wire on the orig motorcraft plugs was completely gone and the gap was 0.100 (shud be .052-.056).
Back in the day it was .49 cents a plug, 4.95 for wires (V8) and you could change them
in 1/2 hour. But then, minimum wage was .75 cents an hour!:grin: