I am now driving a Japanese Toyota Camry; i. It is really reliable and dependable.

I have heard that some parts in the same Toyota model, like the Camry, variedy, though the power is the same.

I have heard that some parts in the same Toyota model, like the Camry, vary, though the power is the same.

I have heard that some parts in the same Toyota model, like Camry varied though the power engine is the same.

I am not sure about it, but I believe different countryies have different regulations on it, and Toyota generally would obey itobeys them.

Are electric-powered cars really greener or more environmental-ly friendliery?

In the contrast, some people worry that more environmental issues could occur whenif power plants produce more electricity than before.

In contrast, some people worry that more environmental issues could occur if power plants produce more electricity than before.

Some people worry that more environmental issues occur when power plants produce more electricity than before.

I am now driving a Japanese Toyota Camry; it is really reliable and depend, a Japanese car that I find reliable.

Grammatically, your original sentence is correct, but it could be better to rephrase so it sounds more natural.

I have heard that some parts inversions of the same Toyota model, like the Camry, varied s although their power engine is the same.

I have heard that some parts inversions of the same Toyota model, like the Camry, varied s although the power is the same.

I'm not sure what you mean by parts? (I don't know a lot about cars)

I am not sure about it, but I believe different country have different regulations on it, andand that Toyota generally would obey itfollows them.

Could also say: I'm not sure, but I believe countries have different regulations and that Toyota generally abides by them.

Are electric-powered cars really greener or more environmental-ly friendliery?

Are electric-powered cars really energeticpowerful?

This is also argudiscussed by many people.

In the contrast, some people worry that more environmental issues occur when power plants produce more electricity than before.

I am now driving a Japanese car, a Toyota Camry; i. It is really reliable and dependable.

“A Japanese Toyota Camry” sounds like you mean a Camry that was manufactured in Japan (not one that was made in China, the US, or Australia, for example). I think you mean it’s a “Japanese car,” designed and manufactured by a Japanese company.

A semicolon feels unnatural in this context.

“Reliable” and “dependable” are synonymous in this context. Using them together is considered poor writing style—too redundant.

I have heard that some parts, even in the same Toyota model, like the Camry varied, some parts may vary from individual car to car (or from country to country?), though the power engine is the same.

Is this what you mean?

I am not sure about it, but I believe different countryies have different regulations on ithis, and Toyota generally would obey it.them.

Are electric(-powered) cars really [energetic]?

What do you mean by “energetic”?

Are electric-powered cars really greener or more environmental-ly friendliery?

This is also [argued | debated] by many people.