98 ranger xlt 2.5 liter 4 cyl automatic.When cold it has a low idle and sometimes dies at stop light/sign.If I let it warm up for 10 minutes the idle remains low but it doesn't die at stop light/sign.Runs okay but not as good as it should.Have changed coil pack,air idle control,tuned up.CEL light is NOT on and it doesn't throw any codes either.