Why does my Ford Windstar 1996 start well and then goes to Limp Mode when warm?

I have a 1996 Ford Windstar that has currently done 233,000kms. I have driven the car without issue for 1000kms over the last month. The only thing it did have was an engine warning light that came on, but no problems were noticable. The warning light was cylinder 4 and 5 misfire.

Yesterday, when I was leaving Vancouver, a few noticable issues started to happen with the engine. I was coasting at around 80kph in top gear. All of a sudden, when slowing down for corners and climbing hills, the transmission seemed to miss a gear, and drop down a gear, causing the engine to rev and the car to stutter. After a brief stop the car continued to do the same, and then dropped into Limp Mode, cruising in 2nd gear until I got it home. It only stuttered when it was changing gear.

I started the car this morning from cold, and there was no issue at all. The car was running like normal. However, after 10-15 mins of driving, the car briefly stumbled, and then went back to Limp Mode. Could this be something to do with the TRS? Any idea what could be causing this?