1991 Chrysler 5th Avenue Fault Code 62

Hello, and thanks for your assistance in advace. The above vehicle with a 3.3L engine is setting a fault code 62. The OEM service manual does not reference this code. From google searches, I found that this fault(although not sure if it pertains to this vehicle) indicates - 62 PCM failure SRI mile not stored. So I replaced the SBEC. Still have the same error. Most of the emission sensors have been replaced on this vehicle expcept for the TPS and Vaccum sensor. I do notice on occasion that car will stall, although, since I have replaced the SBEC, the problem hasnt reoccured(only two days though). The Check Engine light never comes on, but if you check the codes you have 12 - 62 -55. Please also not that I am sure that I am reading the codes correctly. Any suggestions are greatly appreciated.

Chris