Ok.. Geez this is going to take a while... Maybe i should just send you a text book from school?
Engine: All gasoline motors operate basically the same way. I dont want to go too much in detail, because frankly it does not matter, and you said clutch back
You have a I6 so you have 6 cylinders, or large holes. Basically, you have Induction, where the vacumme inside the motor sucks in the outside air, Compression where the air and fuel is compressed together, Ignition where the spark plug lights and burns the mixture of air and fuel, and exhaust where all the burned gas and unburned air-fuel mix, is sent out the tailpipe via vaccume.
Everytime the ignition cycle hits, there is an explosion inside that cylinder, which throws the pison back down, turning the Crankshaft (this cycle is where your power comes from).
The crankshaft is bolted directly to the Flywheel/Pressure Plate, so it turns the same speed as the crankshaft. Now, your clutch is basically a large brake pad. When you enage the clutch, it grabs the pressure plate and spins the input shaft on your transmission. When you push the clutch in, the Throw Out Bearing pushes the clutch disc back towards the transmission, releasing the motor from the input shaft on the transmission, so as not to put a load on the motor. Thats why when you stop with the clutch out, the motor stalls. With the clutch out, the crankshaft (main shaft in the engine) is directly connected to the transmission/transfer case/driveshafts/rear end/brakes/wheels. When you slow down with the clutch out, you are putting a load on the engine, and there comes to a point where the explosion can no longer overcome that load, and cannot spin the crankshaft any longer, stalling the motor.
I need to leave, so more to come later! www.HowStuffWorks.com
... READ UP!
PS. sorry for typos, I dont have time to read over it, but that will get ya started.