jugbutt

I am new to the Jeep scene, So please help me out.

I just bought a 1991 xj cherokee laredo last Sat. for $400.00.
(Will post pictures later)When you get in and start it up (without using the gas pedal) it fires up. I found a jewel in my eyes.
The problem is when you are going down the rode it starts to surge,then when you give it the gas it starts running right til you level off and hold a steady speed it starts back doing it again.'m lost please help.