when i start the car and start driving, the car jerks around in 1~3rpm. like i put gas but the rpm kinda drops abit for a second and goes back on again.
this doesn't happen most of time but mostly in the 1~2nd gear right after i start the car. then it drives fine after.. what could be the problem?

and also, i see little leak between head and the block. it seems like head gasket is finished. is it an expensive repair?

 

im just throwing out basic stuff here but have you

check spark plug wires, plugs, using premium gas?
check timing? distributor cap?
fuel filter?
injectors?

Busted head gasket can also cause serious problem so i would check it out, i heard if you take off your radiator cap and start the car and if it bubbles up alot for awhile, that means your gasket is broken. that or you could have alot of air pockets in your radiator, so good luck with that.
Head gasket probably will run you about 100 but i don't know how much installation is, it depends on who does it, but from my experience pep boys isn't too bad.

 

if you know there is a leak between the head and block why are you still driving it??by now im sure the head is warped