I just bought the MSD street fire coils for mine read all good reviews. But then I have a 4.6

 

Ok I finally got a code thrown and seems like around 1800 to 2200 rpm around 60 mph it wants to "sputter" if I go over 2200 rpm it doesnt cause a issue.

cODE THROWN P0355 Ignition Coil E Primary/Secondary Circuit Fault

My mechanic did mention that the connectors one or two of them kinda fit loose and that the vibration can cause it loose good connection.

Went to Autozone and they only have Duralast connectors at 20.99 each

Ebay had a back of 8 for less then but was not motorcraft brand.

 

Clear the code. Swap coils 4 and 5 and see if the error shows up on cylinder 4 or if it comes back on 5.

 

Great Idea, thanks I will do that, he cleared the code, so I am going to have him switch it out tomorrow when I change the oil.

 

OK I talked with the other mechanic who also worked on my coils and he did replace the connector on #5

So we are suspecting it is a wiring issue, Engine threw a code again, and A/C went out on me as well. This happened before when he was working on the coils. I am not sure what the heck is going on but sounds like a short in the wiring. So I am going to have em inspect the wires and see if it is possible to find any short/bare exposed wiring.

My truck has a sputter around 1800-2000 rpms. When I am at 3000 RPMS it accelerates fine. So it is most definitely coil related just not necessarily the coils. I will have him switch out coil #5 with #4 just to make sure.

This issue is aggravating, I am also going to check with the mechanic if he applied any dielectric grease as well.