Hi there. I have a one-owner '95 Ranger extended cab XLT, 4.0 liter, automatic, 180,000 miles, superbly kept, always clean. interior looks like new; oil/filter changed religiously every 5,000 miles. Maintenance (belts, plugs, wires, fluids, filters, etc.) always done before it's needed.

Recently, has developed a rough idle condition but ONLY after the truck is driven for an extended time (say, an hour on the Interstate) and then ONLY when starting it again (say, after a short stop for lunch). Engine idles like it's got a plug wire loose, or a loose vacuum line. Oddly, though, the idle smooths out after putting the truck in gear and driving off. Doesn't throw any codes (I have my own code scanner); fuel mileage is and has been consistently around 23.5 on long trips and around 18-20 in stop-and-go traffic using 10% alcohol in the gas.

Any thoughts?

welcome to FRF, Richard!

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