Might be the Autozone rotors. At Red Lion Chevrolet we put a few sets of those on and they were pulsating on the first run. Word from the grape vine is the cheaper rotors are the same as the pricier ones from them but they are the rejects. The guy from Autozone told us once when we complained about the pulsation from a new rotor that they require machining before installing. Even the premiums come back within a week with pulsation complaints, whether we turn them or not. Bottom line, in my opinion, Autozone parts are cheaply made junk.
On another note, my truck had Napa cross drilled(dimpled) and slotted when I got it. They were brand new about 3 months prior to buying it and it pulsated. It's a Dakota and had 33s on it at the time but in my opinion they are about useless for the price you pay for them. I was going to buy them for my XJ before getting this truck but people told me horror stories about getting mud in the holes and causing all kinds of havoc. Luckily I scored a set of normal Mopar ones still sealed in the boxes from Craigslist for $50. Usually when we have a Jeep in the shop and call between Napa and Fischel, it's cheaper to buy Fischel's. They have specials on Rotor/Pad combos a lot fo times. For the one 01 Grand Cherokee it was like $100 for the whole package.
Hope some of this helps you out.
