It sounds like the car may have several separate issues.

Has the head gasket ever been replaced? This engine is well known for leaky head gaskets. This can make the car overheat quickly. Or, you may just need a thermostat or your radiator may be plugged. Have you checked that you have enough coolant? Missing coolant can be a sign of head gasket problems.

Sounds like you have an engine idle problem as well. A mechanic can adjust this for you.

On the transmission, you may have a vacuum leak or something more serious. Fist thing to do on this is to pull the dipstick and see what color the transmission fluid is. Does it smell burnt? You can try changing the fluid/filter (easy for a do it yourself'er) as a starting point. It may be low of fluid, so check that first.

Post what you find, and we'll see if anybody can help you...

-GH

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