Admitting he's in for a "difficult weekend", Sebastian Vettel reveals that he is facing a grid drop after taking on new engine components.

Heading into the United States GP weekend, Vettel, like his Aston Martin teammate, is on his third ICE, Turbocharger, MGU-H and MGU-K. While not prepared to specify which components he is taking on this weekend, the German would only admit that he is facing a penalty.

"I think we are heading into, let's say, a difficult weekend," he told reporters. "We are changing the engine and therefore we will have a penalty.

"We will see what we can do from where we start," he added. "Nevertheless, looking forward I think we can be strong here. How strong, we will see."

"You can overtake," he continued, "so I think it is a good place to do and hopefully we will have an entertaining Sunday afternoon and get back in the mix.

"This track definitely is nice," he said. "The first section with the hill, you climb up and then you have the fast esses. It's a good mix, slow parts, fast parts and you just enjoy it; you are happy after a lap to do another one."

Last time out here, the German suffered a suspension failure which was initially blamed on the tyres and the circuit's notorious bumps.

"A couple of years ago, it was quite bad, and they grinded the bumps down," he said. "So maybe in the future, they need to look into it. But I don't know, we'll see what we get out there.

"I think a couple of weeks ago when MotoGP was here it was quite bad. For us, it's not as bad as for them. But we will see. Generally, I'm a fan of bumps."

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