havea 1993 lexus ls400 that hada progressive problem to the point where its not driveable any longer. we changed the plugs and wires then hada mech. look at it he said he coded it and it came back as the mass air flow sensor was bad put a new one on and still have the same problem sounds like its running out of gas when u give it the gas it bogs and starts to die it also backfires any help would be greatly appreciated