Good Riddles

Question: Until I am measured, I am not known. Yet how you miss me, When I have flown What am I?

Question: What sound do porcupines make when they kiss?

Question: Poke your fingers in my eyes and I will open wide my jaws. Linen cloth, quills, or paper, my greedy lust devours them all.

What am I?

Question: John put a coin in a bottle and put a cork on the bottle and later managed to get the coin out without taking out the cork or breaking the bottle. How did he do it?

Question: Paint me up to look real good,
Then take me to the shop to maintain under the hood.
Use a small brush to make no mistake,
Or just replace me with something fake.

What am I?