After how many kilometers or miles should i change the spark plugs and spark plug wires ? thanks?

no i dont think it will work

Depending on the manufactures recommendation. The wires will usually last 45K mile before changing, the Spark plugs on some need replacing at 12, 18 50 and 100K miles, look inside the hand book for the right time to replace the plugs.

the code for evap leak could be from a leak other than the gas cap, and an evap system not working correctly would effect the fuel mileage. If the only code is evap leak, changing the plugs and wires would not fix an emissions leak. when you need a tune up you would get a code saying misfire. these spark plugs should be changed every 30,000 miles and unless they are damaged 80,000 miles on the spark plug wires.

Older vehicles should be checked every 5-10k and replaced as needed. With a 93 you most likely have a copper resistor plugs, and should be changed as needed. Newer vehicles don't need to be checked until 60k and replaced by 100k.

i think the recommended time for spark plugs are every 6 months or somthing dont no about wires

Depending on the condition of the plug it has to be changed.

if it runs fine leave it..if your having problems starting it, poor economy, miss fires...then change the plugs and you might as well change the leads too at the same time all 4

It all depends on the sate of the plug, quite often all they need is a good clean.