Idle is really rough. Normal idle, then it stutters sounding like its getting ready to die, then idles back up and repeats process. Happens when it is below freezing out. When it is below 40 it idles normally with a slight stutter you feel it not hear the change. Any suggestions? Last time it was stuttering this bad it I don't remember what I did to fix it but I got it fixed.

The transmission was out of the truck about a month ago.

 

check for codes....then report back

 

Hasn't thrown any but doesn't mean it won't.

 

plugs ok?

 

I've been having the same problem with my 98 5.4. I did get the check engine light and pulled out the code reader and found it was a bad O2 sensor. I replaced that today however I'm still getting that really bad lug during my idle. Any suggestions?

 

most likely bad coil or plug