sometimes engine goes to idle speed while i'm driving. it feels like i just depressed accelerator for few seconds. then it goes back to normal. in few seconds later it does it again. if i will let car stay with the engine off for few hours, it will be alright.
I can't even predict when it happens. Sometimes next day, sometimes next week
I have no idea why it happens,
please help me to figure it out!

 

it is carbureted, by the way

 

Bump... Anyone knows? Could it be fuel pump?

 

Definately fuel related. I would suspect the fuel filter first before the pump.

 

do you have auto or 5spd? sounds like an auto. when it's dark out start the car and look for sparks. Or during the day spray the wires with water and if the car idles way rough, replace the wires, and filters. You have 2 filters on that car. One in the rear. It's roughly right below the filler neck for your gas tank. Then you have another one in the engine bay. It's easy to get too. if problem still persists, try a small tune up. (cap, rotor, plugs, pcv valve). also try 3geez.com