What could be causing ticking in engine?

An experienced ear is what you need, fuel injectors click but not that loud as a rule, an electrical short from high tension ignition will show up as a misfire, proberbly lifters, when did you last get the engine oil changed?

Just changed the oil yesterday. It has been ticking for a while. I use a website specifically for my car and they mostly say that it is common and you don't have to worry about it, but I want to make sure. I also have an air leak, vacuum I'm assuming. And my car backfires at full throttle only up high in the rpms. I don't know if either one those might contribute to the ticking.

They will not, the ticking will proberbly be a lifter failing, it wont let you down in the short term, but the noise will get worse and you can do long term damage to the cam if the clearance gets to big.