Currently about half the time, when I try to start my van, the key won't turn in the ignition. I tried both keys that came with the van (bought new), as well as a spare. Interior lights, head lights will work. After a few minutes and attempts, it start fine. Equipment lights, clock etc did not display; all began to work after it started. I noted on another posting reference to check engine light and codes. Unfortunately, this has been on for about 50k miles and code check by dealer indicated no problem (no loss of power, mileage etc has shown up either.) It has been suggested the problem might be related to anti-theft malfunction. Supporting this contention: although remote "unlock" worked, "panic" button did not.
Van has 3.3 V-6 engine, 116k, new battery (note: check engine light stayed off for over a week after new battery installed).
Checked for recalls was negative; did not locate any service bulletins.
Any suggestions?