I bought a 1999 STS with 90k miles about a year ago. About 4 months after the purchase it suddenly began cutting off while I was driving regardless of speed or gear. I have to put it in neutral then turn the key 3 or 4 times before it starts back up. I took it to 3 different mechanics -- none of which were able to fix the problem. I had the cam and crank sensors replaced at the first, the fuel pump checked at the second, and the third told me he couldn't help me. I had the motor mounts replaced as well (I see a post below that involves a MM problem).

Everytime I go to start the car, I turn the key without cranking to see if the dash lights up. Sometimes they do, sometimes they don't. The starting usually corresponds with the dash being on or off. On, it starts, off it doesn't. Obviously. The problem is that this happens so erratically that no one can even witness it to diagnose it. It happens maybe once a week.

I've learned to live with the problem, but I am constantly on gaurd especially if I'm driving with passengers. I've come very close to being in accidents because of this problem. (breaking down in rush hour traffic, almosy flying off the expressway exit). But enough is enough...

Can anyone point me in the right direction?

Hi,

Have you already find solution to your caddys problems?

I have year 2002 STS and it's problem is quite similar. In my case motor suddenly shut down and alla gauges switch off. (Only gear indicator in cluster panel is on and radio is on). And after 10-15 seconds gauges will start and I can restart engine. And after that everything is good. This problem occurs about couple times per week.

And in computer faulty codes are some "connection error" problems.
This is very unpleasant situation.

Please tell me what is your situation!

mamyllyl

I have the exact same problem in my 2000 STS. We have discussed it in the Seville forum and it seems replacing the ignition switch is the next step. I am replacing it tomorrow when the part comes in and will post here in about a week if I have no problems.....

Read the following threads going on now over in the seville forum....

Amp Class 2 Data Communication

Bypass Passkey

Both of us had the same problems as you two. I replaced my ignition switch and when I got it out I realized it was the culprit. Over time the terminals on it become badly burnt. There are pictures in the thread. Both of you replace your ignition switches. They are only 25 bucks at Autozone. This should fix your problem and maybe even save your life.....