89 Buick Riviera 3.8 stalls on deceleration; error code 41

I have a 1989 Riviera, 3.8, 35,000 miles. Yes 35,000. When I slow down to turn or stop it stalls. It does not sputter, it cuts off quick. Starts right back up. This would happen very seldom. Now it happens constantly. The error codes were 41 and 42. I replaced the Camshaft position sensor and I no longer get error 42. But It still stalls. Then I replaced the ignition model and the coil pack, but it still stalls and I still get error 41. I read through most of your forum but I did not see anything simular. I would appreciate any suggestions. The books I have list alot of possibilities for code 41.