1990 Cadillac Seville running bad

I have a 1990 cadillac seville with 160,000 miles on it. The car is running bad and im getting bad gas milage. It has a miss and it backfires. It backfired and blew my muffler apart so I had a new converter and muffler put on it. When it backfires and jumps and loses power I stop and turn it off and start it back again and it runs fine for a while. I have replaced the plugs, wires, distribitor cap, rotor button, oxygen sensors, egr valve, pcv valve, ignition coil, ignition control module. I was going to replace the throttle position sensor and camshaft position sensor. What else could be causing it to act like this. I had a garage hook it up to the computer and 13 codes showed up. The bcm and ecm was a couple but I thought if the computer was bad it wouldnt run at all. Any ideas what I am missing? I am changing the throttle position sensor this week and I was trying to find a price for the camshaft position sensor but I think it is called something else. In the haynes manual it is called the camshaft position sensor and it is located under the rotor button but advance and autozone didnt have it listed in their parts for that car. What other name could it be under?