1999 Ford Taurus Engine still "missing"

I have changed plugs & wires, fuel filter, air filter, oil & oil filter and both O2 sensors. Car still has a miss to it. Making a "putt putt " sound from the exhaust pipe.

Otherwise, car runs fine. Only misses at idle or when car is in park. Can anyonesuggest anythig else to check?

** I also replaced the ignition coil. **