hi cadillac friends

i've a strange problem with my 81 cadillac with 368 v8-6-4.

when i accerlate with 3/4 or full throttle from zero i always get trouble code 24 with always on check engine light and dispclacement/cruise controle are disabled through ECM.

same problem is on hills, when car stays with hood up the hill and i accerlate 3/4 or full its the same, or on a parking place when i turn steering wheel in one side totally and accerlate with more throttle...

same problem on following procedure:
stand: short 3/4 or full throttle (only 1 or 2 seconds) then no throttle, there is error 24 too and check engine is and stays on.

the procedure in the service manual i don't understand, because code 24 tells vehicle speed sensor!!!????

has anyone an idea?

thanks a lot

adrian