about 10 months ago I had this same problem, my check engine, emissions light was coming on. At that time I had just purchased the car so I took it back to the dealer and he had his mechanic work on it, They said it was misfiring and that replaced the plugs, that didn't work so they ended up replacing the head. Now I am having the SAME problem again!!! I checked my gas cap, and all was well. When i start it up in the morning it is fine, then when I go inside while it is warming up I come back out and it is spiking from 1 - 2 rpms, I am still driving it because at this point I am in shock, I have been careful and tried not to rev it up too much. What is the deal with this? Can this really be happening again? I don't think I will get off so easy this time!