I have a 1988 silverado that I am have problems with the ground signal from the computer that locks the torque convertor up(700R4). My question is does anyone know how to troubleshoot the speed sensor and the MAP sensor with a typical volt meter. From what I have been able to find out these are the sensors that the computer looks at to know when to supply the ground for the torque convertor lockup. Does anyone know what else that the computer maybe looking for toknowwhen to lockup the torqueconvertor up. Thanks Kevin