My idle has been hanging for the past month. I've had an MIL light, code was for the driver's side front O2 sensor. That was replaced but the light came back and driveability didn't change. I do have an aftermarket catted X-pipe. I just replaced the battery last night and now the car has been constantly stalling. My voltage also looks a little low. What could the issue be? Should I check my ground strap? I'm thinking it's either an exhaust leak or an electrical issue. Could my alternator be going? My battery hasn't been dying.