Does my 1988 740 turbo have either an ignition system control unit (different from the LH control unit) and/or a charge air overpressure switch. In the Volvo green book both are included as components of the LH 2 Jetronic system and are pictured as being located above the gas pedal. Does my car have either of these and what do they do? Could either cause the ignition to shut off instantly. Intermittently, the engine just quits....instant shut down. The usual suspects have been replaced including fuel pump relay, radio suppression relay, and air mass meter. Thanks for all suggestions/info.