can a bad spark plug cause a loud squeal when firsr starting engine?

Those are all wonderful answers, well, most of them.

Here's what happens.

As your battery just sits there overnight, it looses some of it's charge supplying power to the clock, radio memory, computer, alarm, etc.

When you start your car in the morning, the starter draws a tremendous amount of energy from the battery to turn the engine.

Then, when the engine does start, the alternator tries like heck to put all the energy back into the battery as fast as it can. (that's it job)

Anyway, while it's doing that, the drive belt (serpentine) is trying it's darnedest to turn the alternator.

If the belt is old, or loose, or even dirty, it will slip on the alternator pulley as it tries to turn it.

After the battery has gotten charged back up a little bit, it needs less and less power from the alternator, and the belt can more easily turn the alternator.

ADDED:

Let me say by the way, a belt is a lot cheaper and easier to change than anything else you mentioned. Start there.

You probably have a bad belt. And it depends on what car you have if there is a separate belt on the AC. And no, a greasy spark plug will not cause a loud squeal. Don't go replacing everything on your car because of a squeal. First, replace your belt(s) and go from there. Or just take it to a qualified mechanic if you're unsure.

I've heard of a power steering pump doing this also the ac pump could be locking up. loosen the belt and see if these are hard to turn by hand. If it turns out to be the ac and you don't have the 1k to fix it you can get a bypass pulley for most cars at the local parts house.

Plug gap (the distance between the electrode tip and the center electrode) not being correct will cause the plugs to misfire or not fire at all. You also need to check the timing, plug and coil wires, the distributor (points. rotor, cap, or solid state type) the coil (or igniter in the newer cars) and even the ignition switch and wiring. (I've even seen the gear on the bottom of a distributor strip, the timing belt/chain break or jump a cog and the cam sensor as used on some newer vehicles go bad.)

I would go with the belt option. pumps are expensive and belts are cheap. belts do power the a/c among other things, but I would definitely go with the belt.

spark plugs don,t make any noise.on some cars there is a separate belt that runs the AC. you don,t say what kind of car you have.

If you have a newer model car then you need to change your serpentine belt. It's usually squealing from the alternator

video

http://www.wonderhowto.com/how-to/video/how-to-ins...

im guessing its the water pump, i had the same problem on a 98 ford tourus.

i think youve got a bad belt, or misaligned. if you have an oil leak that oils the belt, then that could do it.

COULD BE A BLOWN HEAD CASKET, HAVE A COMPRESSION CHECK ON THE ONE PISTON.AND ALSO LOOK TO SEE IF THEIR IS ANY WATER IN THE OIL,EVEN LOOK IN THE WATER FOR OIL.