1990 Chrysler Le Baron car loses power

i did a tune-up hap the catli converter changed i also changed the fuel pump an fuel sending unit an now when i drive my car it drives fine until it get operating tempture it start to lose power when i step on the accelirator it starts to put an an i take my foot off the gas petal it surgest then start to lose power again and when i push the gas petal it starts putting again and it gets worse when im going up a hill