vw city golf mk1 2003 model
1.6i

when i start up the engine the engine makes this wierd tick tack noise like something is hitting against something .

it idles very low and the lights seem to flicker like the car is gonna cut out

when i rev it the sound stops when i drive it also stops

im new to all this my first car wanna figure out what it can be

any advice

Could be hydraulic lifter that has failed or does not hold pressure.
What is the service history like on your car?
Serviced regularly?
What mileage on motor?
Does the idle stay low when car is at temperature?

bought it second hand

when the car warms up the idle still shuts down
i ajusted the excellaration cable to bring the idle up now its driving normal but takes to much fuwl