2004 Cadillac CTS • 6 cylinder • 90,250 miles

I have a 2004 cadilac cts with 90248 miles when ever I accelerate above 60mph my starts******** but does it for a short time and the stops and then starts up again I took it in and they fixed it twice but nothing helped they fixed te pin and rack and a bushing on my transmission and the problem persists I think it might be an o2 sensor due to the miliage but wanna make sure thanks.
January 1, 2011.

I don't understand what is meant by 'starts********', and I am assuming te pin and rack is the steering gear, and the bushing is the rear diff support bushing. I need a little more specifics on the symptom.

Jan 27, 2011.