Two problems related to ignition have been reported for the 2003 Ford F-150. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2003 Ford F-150 based on all problems reported for the 2003 F-150.
My '03 f150 fx4 4x4 has what I suspect to be an ignition problem that the local dealership service department cannot duplicate or diagnose. I have had the truck since July 03 and it has been to the dealer twice. Once without a "service engine soon" light and I was told they could not work the truck due to warranty issues without the light. Then in November the light illuminated and I took the truck in for the light and the four wheel drive inoperable. The four wheel drive was fixed by replacing the front differential, right side axle housing, shifting fork and gears. But the ignition problem was just as illusive with the light and the code. Now I still have the problem of the truck dying out as usual and my fuel economy is degrading. The truck will die out and recover causing the truck to buck severely, possibly causing the 4x4 problems mentioned earlier. It is at its worst at 1450 rpm or 59 mph. Once 1500 rpms are exceeded the problem is gone. I can also accelerate through it without experiencing any problem. Just steady-state operation without any load and it will die out repeatedly.
Just had my 2003 f150 5. 4l fixed after the #3 spark plug blew out. New plugs and heads cost me $4000. 00. The heads are the updated version Ford now has. The original were 3 threads, allowing for the plugs to blow out before the 100,000 plug replacement. They now have 7 threads. Ford needs to recall and repay us.