Showing a random cylinder misfire. Replaced plugs,wires, distributor and rotor . Still showing random cylinder misfire. Ive been told i have a bent valve. But im not a mechanic so i have no idea what to look for or how to find out the problem. Please help

 

Have a cylinder leakdown test performed.

 

Have you narrowed it down to a cylinder? Try swapping injectors around to see if you can isolate it.

 

it could be spark, or it could be fuel.
you could get a "test spark plug" to make sure they are all firing. then You could pull your fuel rail with injectors attached and crank to make sure they are all squirting. If all that's good, it might be a timing problem.
I wouldn't think bent valve first, but if one was bent, you'd have low or no compression. So then I'd do a compression test.

 

Check valve adjustment clearance.
Manual states 90Kmiles, but you would be better off checking every 30Kmiles.
Valves that are too tight, especially the exhaust, will hang open when hot and lose compression.
No compression, no combustion.
No combustion = misfire.