Just bought an 06 5.4 screw and got the plug change out of the way. The truck runs quite well . Especially after a 200 k haul down the highway!. One thing I have noticed is that every once in a while I will park the truck say at a store. run in and back out then fire it back up and it idles rough when in park. I will run it to my next stop 2 miles away. repeat the process and it idles fine. It does the rough idle only 2 or 3 times a week. I was wonder if reseting the trip computer may fix this as it is really intermittent and my thoughts are if it is mechanical, it would run rough at idle in park most of the time. Any ideas??

 

Possibly the IAC ( Idle Air Control). Try cleaning it first if that doesn't work then it may need to be replaced.

 

I am familiar with the MAFS and cleaning procedure which i will try tonight ..I read through some posts on where the IAC is but how do you clean it?

Thanks

 

I dont think the 04+ 3v's have an IAC..

 

You would be right jethat. Well I guess you won't need to know how to clean it. Keep an eye on me jethat I start thinking about what would cause the problem without paying attention to the model year. Thanks.

 

Possibly intermittent leaky fuel injectors?