engine rattles/slow acceleration

What is your question?

For the past few days, I hear a rattling noise in my engine for about the 1st 15-20 minutes, then it goes away. While the rattling occurs, acceleration is much slower, and I even feel a little hesitation while trying to accelerate. When the rattling stops, I'm able to accelerate as usual. FYI - I had a gasket replaced and an oil change last week. Anyone that can help, thank you in advance!