as far as not going above 3k... I would say cat as well. I had a car that did that exact thing one time. Drive the car at night and "push it". after you get it good and hot, stop, get out and look under the car at the cat... if its glowing red, then its stopped up and you need a new one.

I wonder if the ticking noise is tripping out the knock sensor and cuasing it to pull buttloads of timing out?