93 honda accord lx

I have a 93 honda accord lx with 194,000 miles. When I hit 70mph and up, my engine starts to make a roaring noise. when I fall below 70mph, the noise goes away. I can also feel the car struggling to shift or even stall for a sec while accelarating after 60mph. But once it hits 70, the roaring starts. sometimes it feels like its about to turn off or break down while pushing on the gas to increase speed from 60mph and on...any ideas?? THX

Mike