need help with car problem

Tried searching but couldn't find an answer to my problem. I started my 02 Alero with 148000 mi this morning. Start reversing and the service engine soon light starts flashing. Stopped and turned off the car, restarted couple minutes later, Now the SES light is steadily on. Try reversing but car can't make it out of driveway. Driveway has a slight incline( 25 degree angle). Car will make 3/4 of the driveway then the engine will start idling, also the exhaust doesn't sound normal & inside the vehicle smells like burnt plastic. Any help or info would be helpful