I have the same problem on my 96 Skylark. After a couple of years of reliable starting, my Skylark started flashing a "Theft Detection" light. Once the switch was turned off, sometimes it would re-start after a few tries, sometimes it would be weeks before it started again. The last couple of times it died, I had it towed to my local GM shop. In each case, it started fine once it got to the shop (I am wondering if the car being bounced around by the wrecker might have done something)? The mechanic hooked the diagnostic computer up to the vehicle and found no error codes being displayed. In each case, it malfunctioned again shortly after I got the vehicle home. The last trip to the garage cost me $200.00 for a reprogrammed key. The mechanic said the key might not be sending the correct code to the computer. My key does not have a chip on the key, so I am going to assume I might have been taken for a "ride".
Now, my instrument lights are no longer functioning either. I have checked every fuse in the vehicle (both in the dash and under the hood).
Does anyone have any idea what I might can do?. The last time I talked to the shop, they wanted to dismantle the dash and send it to Detroit for further troubleshooting. I would really like to avoid any more "blind guesses" from the shop. Any ideas would be greatly appreciated. Thanks