My 2002 Mustang GT with the 4.6 L V8 and automatic transmission has had an intermittent surging at idle. Not it is running very rough and has very little power. I used an inexpensive code scanner and I did not show any trouble codes. I was thinking of changing the fuel filter. Has anybody had similar issues? The Mustang has just over 66,000 miles on it. I changed all of the sparkplugs and the coil pack on number 7 cylinder several months ago. It showed a trouble code at that time.