I have an intermittant problem in my ECM in my '89 Firebird VIN 'E' TBI w/5-speed manual. I want to get a different ECM out of the boneyard and put my PROM and the other chip in it. What other years or vehicles have the same ECM? The ECM's I have seen in Camaros and other Firebirds have different GM Service numbers on them, The guys at the salvage yard say it doesn't matter, just put swap my PROM and the other chip into it and it will be fine. Does anyone know if this is really the case?