My wife's 2004 Sunfire is shifting really hard. Have done a complete fluid and filter change. I had the car to the transmission shop where they said the tranny was all good. The cat was plugged so had it replaced. Had an overall checkup done on the car and all checked out. When you pull away from a stop it will hang in 1-2 gear until 3500-4000 and then clunk into the next gear. When you pull away from a stop you don't know if your going to have enough power/speed to merge into traffic. I find if you shift it into 3 and pull away, it seems better. When you leave it in D (four speed) this is when it seems to start acting up. I am running out of things to check and look at. Any suggestions would be greatly appreciated.