97 Bravada Check Enging Light

I have a 97 olds bravada that the check engine light is on. I was told it was an O2 sensor that needs to be replaced and that right now it won't hurt anything. I have not had a chance yet to replace the O2 sensor but just yesterday once I got on the highway and pushed on the gas the car wouldn't go, the check engine light started blinking on and off and it smelled like it was starting to get hot. It felt like it wanted to move but like it was being held back. Now after awhile the car runs fine. Is this just the O2 sensor or is it something bigger. Any help would be greatly appreciated.:confused:

Easiest way to figure out whats happening is to get the engine codes. That'll help figure out whats causing the CEL. You can get the codes read at a local autozone etc.
Pretty sure your Olds is OBDII