My 2004 Disco (133K) has been really cranky while running the AC and driving in city traffic lately (stop and go, slow) and is having a hard time shifting gears.
I recently drove out of the city, mostly highway driving and didn't have the same problem.
I know that it prefers a less hot and humid climate (Like a true Brit) because she always runs much better in the cooler months. But I need to use my car in the summer in NYC (90+ the past few weeks)

Any ideas what's causing this & How to remedy?
Thanks.