what would happen if i drove with a bad opti for a long time would my car still run, start.

 

It'll run until it doesn't. I drove around on a bad opti for awhile and then it finally went out and I was stranded. If you know it's going out and have the means, go ahead and get it replaced.

ShaunB

 

what are the signs of it gong out and how much to replace?

 

mine would just stumble from time to time and I really noticed when my dyno graph was jumpy like a cricket on crack. if it has weird dead spots at weird times that can be a clue.
I think it was about $150 for a rebuilt Opti. My dad helped me put it on (I held the flashlight and supervised).

ShaunB