22nd Jul 2011, 12:24

Problem with stalling on the '99 STS. I had the same issue with my '98; it's the crankshaft position sensors (it has 2). I spent LOTS of money fixing other could-be issues, and it was for sure the crankshaft position sensors. Since my repair, my mechanic has done 4 more of the same jobs, all on various 90's GM vehicles.

30th Jul 2012, 00:57

Have the ignition switch checked. When your keys are in the ignition, shake the key to see if the dash lights go on or off, or flicker. If they do, it's the ignition switch. I had a hard time convincing my mechanic, but after he replaced the fuel pump and it would cut out on me, he finally listened. I have not had any starting or stalling issues since replacing it. It's an old school lesson. Don't put any keys but your car keys on that key ring, or the weight of all the keys will wear out the switch.