I have a 90' 740 with the b234f and having the same code 232,I spent many hours trying to track down vacuum leaks,resealed intake manifold at head and throttle body with a cleaning and adjusting, cleaned electrical connnectors, ect.Fuel trim code 232 either means too rich or too lean at idle,and the computer has compensated as much as possible.I have checked and replaced the FPR,injectors,MAF sensor,O2 sensor,cool temp sensor,cap,rotor,wires and coil checks good.Nothing really stands out as being really defective.I want to try a "928" fuel computer as I think the car is just running lean,I don't have a Ex-Gas analyzer to see for sure,I will have to find a local shop that has one and perform the test outlined in the book to see if in fact the fuel ecm is at fault.Hope this helps.