Something is wrong....don't know how serious, please help
 

Alright. Bare with me. This is a new problem so I will try to explain it to the best of my ability. From the beginning: The car is an 03 Bonne

About three weeks ago I was on the express way coming home and I had cruise set at 75. All of a sudden the low trac light popped on and kicked my cruise off. Weird but the car wasn't sounding or acting funny so I reset cruise and kept going. Mind you I don't drive on the e-way ever b/c I'm terrified of them. So nothing else happened until two days ago.

That is when the check engine light came on and stayed on so went to Auto Zone and had them scan it. It came back with the code P 0420, catalyst efficiency. From what I think I understand about that is that it could be the exhaust, O2 censor, caddalidic converter, etc. Didn't get a chance yet to figure that out b/c just found out about that yesterday.

Had to go to Flint today so we took my car. The same thing happened as the time on the e-way. But about two dozen or more times. This time though when the cruise kicks off it jerks you really hard to the left every time. And now there is an alert that comes up saying "Stability System Active". That came on every time except two. The other two times the light came on and the came made the alert noise (ding,ding) And read "Service Stability System"

It's really weird and I am afraid to drive it now for fear of what it might do. The odd thing is that it hasn't ever done it until you go faster than about sixty-five and the cruise is set.

I believe that your issues are unrelated. On the first, either the cat, or the rear O2 sensor could be bad. Any performance problems once the car warms up?

The service stability system warning is usually caused by the steering position sensor. However, that generally has not activated the system. You'll likely have to take it to a dealer, or somewhere that has a Tech II or similar scanner to find out what the problem is. Besides the steering position sensor, a bad wheel speed sensor in one of the hubs, the lateral accelerometer, or yaw rate sensor could also cause the problem.

I agree with archon's assessment.

Thank you guys so much. at least now i have a direction to go in

I rarely use cruise control but I was in the states this week and I used it, everytime I went over the thump that partitions every 30 feet or so of asphalt it kicks my cruise off.Needs to be a smooth road.