My truck runs and drives great (3.5EB) and has great service history from the previous owner, but at 57k it has just enough of a rumble/faint rough idle after cold start to bother me. It smooths out mostly when the truck is up to temp.

In the last 2k miles I’ve done an oil change, replaced the plugs, and verified the dealer put a brand new air filter in the truck. I also ran 2 bottles of Techron through the fuel system and I run 93 octane. What would be your next step in eliminating that last bit of rough idle?

 

Italian tune up?

 

Do one of those about every day

 

Take the intake tube off and clean the throttle body. I use a clean, lint free rag saturated with rubbing alcohol. It immediately cuts the carbon buildup. Pay special attention to the butterfly edges and the back side of it, and reach in as far as you can. You can alternatively take the throttle body off to completely clean it; I have never felt the need.

 

I’ll give that a try!

 

What spark plugs?

 

OEM Motorcraft

 

May be slightly early, but I did mine at 75k when I did plugs, I also did the COP boots and springs as well.