What could cause a ticking that doesnt go away?

What is your question?

Just recently bought a Mazda Protege with 158000kms on it. I noticed that there was a ticking sound coming from the engine and my check engine light had come on. The speed of the ticking increases as I accelerate but remains even after the car is back in idle. I figured it may just need oil/oil change, but was wondering if there are any other possible causes.