Sputtering/dying/loss of power after ideling/almost over heating sitting still

Check for a clogged catatlic converter or muffler.

Thank you very much! It has, at times, been giving off the "rotten eggs" smell of a clogged catalytic converter. We'll start there. Thank you

Don't know if this helps narrow down further to that too, but my gas milage has gone from 16 to 18 mpg to 12 to 13 mpg all the sudden in the last week. And my ac goes from cold to all of the sudden it's just like you turned the vent only on when the engine temp starts to climb. We just got it back from the shop for linkages and new alternator. When it rains it pours

Thank you we will check all of these