Re: 98 SHO on the blink
I have a 98 SHO myself, and experienced the blinking THEFT light last year. I believe it was blinking a two-digit code by blinking rapidly a set number of times, pausing, and moving to the next number. It repeated this pattern over and over again.
Before I had a chance to research the code, my battery died. After it was replaced, the blinking never occurred again. I concluded that my battery was weak (old), and the drain of starting the engine briefly lowered the available voltage to a level unacceptable to the alarm system.
After the battery change, my engine also ran much better. I recommend you get a battery test or replacement. It may quickly restore your SHO to its old self. Good luck.