not wanting to go past 30 or up hills

[kait]

i have and 87 240 and last night when i was driving i was going about 40 the car decided it was to much work and stoped accelerating. Then i released the gas and hit it again it didnt want to go over 30 though. Then it seemed fine until i had to go up a hill. I started it this morning and drove and it seemed fine. The only problem i've noticed is that the timing is off when its suppose to switch gears. now i know almost nothing about cars so i need some ideas on what it could be.