F150 misfire

I have a 2001 f-150 with the 5.4l engine. every once in a while I get a surge that cause the engine to run real rough. It usually happens at about 40-50 mph and approx 1200rpm. Had it happen once before and replaced a bad coil on number 5 but this time no codes are showing. any other ideas.

I had the same problem on my 01 5.4 back when I first bought it and it was also the coil. The only difference is mine never threw a code, so don't rule it out.