I have a 1994 Buick Century special. 81,000 original miles. Shifting problems.

What is your question?

I have a 1994 Buick Century special. 81,000 original miles. My main problems are, it tends to almost die once awhile when in parking maneuvers like from reverse to drive and it will tend to idol very low at times and the main problem is at higher speeds, it doesn’t shift out of 3rd, I found this out while on highway going 60-65 and in 4/OD and shift into 3rd and nothing changes. It does fine shifting up n down between 1st-3rd...

What makes this problem better or worse?

When cold

How long has your 1994 Buick Century had this problem?

One year at least