Sounds like what mine was doing. It was actually running the same diagnostic check that is run when you first start the car. After several months they replaced the ignition switch and the PCM. That seems to have fixed the problem. BUT, it now thinks the key is in the ignition when it is not, the fobs do not work right, the trac-control light stays on at times and the car locks itself.
I talked to another '06 owner at CTR who's PT was doing the same thing. So do not let them tell you they have never heard of this.
