Grand Am stalls

I have a 97 GA with 2.4L engine with 165K miles. In the spring or fall when the temperature changes, my car stalls when you come to a stop after running on the highway, like you are not pushing in the clutch. It will start and sputter, and stall. If you let it sit a while it will be OK. This only happens when there are temp. Swings, if it is 45 in the morning and gets to 75 during the day. In the summer and winter it runs fine with no problems. I thought it may have been TCC but Tran. Shop said they did not see any codes, but they are changing the fluid as I type. The codes he did see seemed to indicate a fuel-air mixture problem but he could not tell much. I have had it in before to the mechanic but no one has ever found anything, and of course it usually runs fine when they have it. This has been happening for years.