i have this problem--at start up- idles rough and even after warmimg up for a good 5 minutes it will have zero throttle response or sputter and misfire-- i rev it up a few times it gets better then improves with driving but only in the morning till it gets warm...then for the rest of the day its fine... i changed the plugs-wires and coil packs. everymorning the code will come back- i get to work- take out my dianostic tool and clear the code-- does not come back till start up the next morning. searched this thread here but no real answers?

 

Mine is throwing the po 300 and 301 right now. It has done so 3 times now. I clear it and it comes back.. Mine idles real rough at start up and smooths out after 10 seconds. But still idles rough all the time. Just worse on a cold start up.. I am taking mine in on Monday. I will post what they found and did.. Its under warranty so I will let them do their thing first..

 

What about the plugs?

 

usually a cold start misfire is plug related....

 

changed the plugs-coil packs-o2 sensors and now changing the coolant temp sensor....ughhhhh

 

If your o2 sensors were at fault your ECU would have thrown a code for your O2's gauranteed.

Do you have pics of what your spark plugs looked like so I can help you narrow this down? Other causes for this could be a vacuum leak or faulty fuel pressure on start up because there is no pressure in your line when first start up when it's cold not very common but its worth looking at.

 

well changed the o2 sensors and the code has not come back now-2 days! fingers crossed.