1993 Honda Accord Runs Sluggish

Hello,

I have a 1993 Honda Accord with a 5-speed transmission. I recently had an oil change, PCV valve replaced, and a radiator flush and the car was running fine. Today however, the car would not accelerator over about 55mph no matter how much gas I was giving the car, or if I was in 4th or 5th gear. It seems to run fine other then that, no unusual smells or emissions that I can tell, the car isn't overheating, the check engine light isn't on, and the car accelerators normally up until the speed gets to about 50, where it will slowly accelerator up to 55. I'm not sure what is wrong or if I should be driving it at all.

Any help would be appreciated

Mike