my car has only 2/3 of the power it did about 2 months ago and it has been easily driven. i gave it a full tune up and its till not running tops. please help any suggestions would be much appreciated.

Year, make, model, engine size, and what was done to it since the last time the engine ran good.

Did you over heat at all? My 350 lost half it's power and it was a bent push rod and valve. What type of noise is it making?

Could be alot of things, check the simple stuff first. Is the ignition timing correct? Maybe check for a vacuum leak, secondaries not opening up? Etc.....

fuel filter getting clogged will do the same thing....and slowly get worst.