I have the '92 740 wagon. It starts, runs one or two seconds, then quits. If I give it gas, it will run at higher rpm, but dies when I let off. The IAC tests good, The Mass air meter tests good, but the manifold pressure unit has no voltage on its terminals. The eror code is 1-2-1, and will not reset unless I disconnect the neg battery cable. This is a bosch jetronic 2.4 system. Does anyone know how to properly test the map unit? Mine has two leads plus the one inch hose going to the intake manifold. I disassembled the map sensor, and inside is a small solenoid that looks like a relay. When it closes, it opens one air passage, and plugs up the other one. I can't figure how the peizo signal gets put on the two leads to tell the ecu what is happening. Could my ecu be bad? I don't want just throw parts at it, like they do at the dealer.