TM10-3930-660-34 (2) Excessive oil consumption is generally caused by leaky gaskets or loose line connections. (3) Always check the easiest and most obvious things first.  This simple rule saves time and trouble. e. Double check before disassembly.  The source of most engine problems can be traced to more than one part in the system.  For example: (1) Excessive fuel consumption may not be caused by the fuel pump alone.  Instead, the trouble could be a clogged air cleaner reducing air inflow or a restricted exhaust passage, causing  abnormally  high  back pressure. (2)    Engines very often are  disassembled  in  search  of  a  complaint  and  the  real  evidence  of  the  problem  is destroyed.  Check again to be sure an easier solution to the problem has not been overlooked. (3) Check all tags, service request forms, and vehicle logbook for repair history.  This may help lead to the source of problems. f. Before attempting to correct a problem, diagnose the cause of the problem.  Do not allow the same failure to occur again. 2-5. EXPLANATION OF COLUMNS. a. Malfunction.  Visual or operational indication that something is wrong with the 6KVRRTFL. b. Test/Inspection.  Procedure to isolate the problem to a component or system. c. Corrective Action  Procedure to correct problem. 2-3