Just the p0300 code, which is stored and pending when I check the codes, so its on going as the car runs.

I'm pretty sure the wires are on correctly, considering the lengths. I didn't reference a diagram or anything though.

Which are the correct plugs, I didn't replace the plugs myself, they were done at the time of purchase from the guy who sold me the car.

I don't have any power loss, it accelerates in the lower gears fairly easy.

With checking the ground, how should I go about that? Im not sure where its located to be honest.

I haven't changed air filter, oil, or a fuel filter. But looking at the air filter it is a little dirty. I should do these things then too.

I appreciate your detailed response!