I have a 99 blazer 4x4 2dr. with about 150k miles on it.
Quite a few people are telling me I should have the timing chain replaced.
I still have the origional one and the engine is running fine.
Is there a real need to replace it even though the engine runs fine?

 

You can if you want to spend the money. Or if it will make you feel better. But it's not something that's replaced unless you have everything in that area taken apart already.