First I would like to say hello My name is Jared and I own a 2006 Fusion, recently purchased 2005 Freestar and a 1992 Ranger.
My 2005 Ford Freestar has a very noticeable misfire from idle up to 2200 or so rpm. With no codes. Being that there were no codes my first thought was fuel or ignition coil. Changed fuel filter as it was time anyway and took the coil out. All secondary resistance tested around 10.8 kohms, all primary resistance was around .3 ohms. All within normal range.
What I have done so far.
Replace Fuel and Airfilter
Check coil. = good
Check PCM for evidence of water intrusion. = good
Hooked up scanner and went for a drive.
TPS voltages all normal.
Replaced Camshaft Position Sensor.
Hooked up a timing light to all spark plug wires. Every single cylinder showed irratic flashing.
Irratic strobe is present above 2200 rpm. Gets hard to tell around 3500 rpm
The only thing I can figure is something wrong with the Crank Position sensor such as a intermittent short to ground or maybe the PCM is bad.
If anyone has any insight it would be greatly appreciated.