my car has 67k miles on. i bought it with 18k in 2006 and i've never had any problems with it. in july i drove it down from wisconsin to north carolina, where i'm stationed. in the last month it's started acting up. when the car is fully warmed up and going in excess of 50 mph in 5th gear, i hear a droning noise--almost the same sound as a vehicle with large size tires makes when it's going highways speed. there's also a strong smell of burning plastic. the strangest thing is that occasionally i'll be driving along in 5th gear, going about 55 mph, and i'll mash the gas pedal all the way down and it won't do anything. however, i can downshift into 4th, the noise stops, and the car is responsive when i hit the throttle.

so all of these symptoms seem to occur sometimes once the car is fully warmed up:
--strange road noise in 5th gear
--lack of, or no acceleration in 5th gear
--smell of burning plastic

no CEL lights are on, fluids are fine. i've only put 1200 miles on this car since july. i have no problems with gears 1-4.