My petrol car sounds like a diesel?

I have a 1.8, 10 plate ford focus with only 60.000 miles on the clock. I've recently noticed that the engine don't sound like it used too when I first brought it. I also noticed a clunking sound when engaging the clutch, I used to be able to get 130mph out of her but I'd be lucky if I get 120mph now, she don't preform like she used to. I don't hammer the engine and treat the car bad, I've had it just over a year now but why the sudden loss of power? Much appreciated for those who read and reply thank you!

So let me get this straight. You have a car with a very small petrol engine that sounds more like a diesel. You've pushed it up to 130 miles per hour and you don't treat it bad? The engine is under tremendous stress at those speeds and being so small, its not made to sustain them so of course you're going to break it and it won't perform like it used to. You sir, are an idiot.

Fuel filter, injectors clogged, fuel pump weak, fuel pressure regulator, could be anything related to those.

Ford build CR4P engines down to a price, not UP to a high standard.