Whenever I start my truck and the engine is cold, whether I am sitting in park or whether I start driving, when the engine gets to an idle, the RPM's will slowly drop from around 1000 down to around 6-700 (which is normal) but before it gets down to regular running rpms, the engine seems to shudder and the RPM gauge will go up and then drop and up then drop and shake. If you give it gas the engine revs smoothly. I already replaced all the plugs when I bought the truck in March with the Motor craft plugs. Could this be a Coil Pack going out?

 

Is it throwing any codes?

 

is this only when it first happening on intial start up, or after coming to a stop and idle after normal driving, or both?

 

its not throwing any codes, and its only until the truck gets up to average operating temperature. Once the truck gets warmed up it rides just fine, but until it gets warmed up when it idles it feels like a misfire. I'll try to get video of it so I can show what I mean.

 

its doing the same to mine. i been trying to diagnos it at work, and it looks like the idle air control is acting up. it's one of those repairs tht, tht until it breaks, dont worry about it

 

does that mean its a PITA or Expensive repair?

 

the part itself is about 50-60 bucks, and roughly .5 to 1 hour of labor. i just been putting it off on mine, til it finally breaks