as much as needed
under a plate in middle of valve covers. 3 spark plugs are located in the right side of the air intake and the other 3 if you have a v6 are located in the left side under the air intake casket which will require you to remove the casket. If you don't know too much about cars you should probably go to a mechanic to change the spark plugs.
It should be OK if it isn't too much. The engine will probably burn it but it could poissibly cause the spark plug to foul and not fire; requiring one to remove it and clean it. It will not RUIN the engine.
Spark plugs are around $1.50 - $3 a piece... depending on how many you have $2 x amount of spark plugs = amount it should cost Probably no more than $20
Norton should be able to remove it from your pc.
If you are asking about compression numbers, they should be around 150psi.
Garlic will not remove fleas from cats.
On the left side of the engine there is a rail with 3 rectanglular coils. there are 4 bolts attaching it to the cylinder head. remove the 4 bolts and pry it away from the head (if needed pry alternate sides to remove all boots from the spark plugs). If needed there is a connector near the back of the coil rail that can be disconnected by pushing the red slide tab outward then squeezing the tab on the connector while pulling it off the rail. Then remove the spark plugs. insert new ones, reverse steps. Be careful not to use too much force on the slide tab. they break pretty easily although they arent completely necessary.
Since it is a horizontally opposed four cylinder engine, the spark plugs are basically installed the same way (horizontal to the ground, in line with the pistons) Two are on the left, two are on the right. The coilpacks replace the conventional spark plug wires. You will need to remove the coilpacks to access the spark plugs. You will also have to remove the intake airbox to reach the left two spark plugs, and you will have to remove the windshield washer fluid reservoir to reach the other plugs. This is very time consuming... the right tools make it much easier. Make sure you get the oem replacements, otherwise your car may not run well.
It unthreads much like a spark plug. I would unplug the electrical connection then cut the wires off the sensor. This will let you slip a 7/8" box wrench over the sensor. Remove by turning counterclockwise, it may take some force to break loose.
If you need to ask this question you should not be removing palm trees.
spark plugs tend to foul because too much oil builds up around the plug and it cannot work correctly. *sometimes* you can actually remove the plug, clean it, re-gap it, and replace it in the bike.
Normally white, possibly a little blackened, but not much