Agreed. More likely ignition/electrical.

I think the quick jump in fuel pressure is happening beceause the injectors are shutting down a fraction of a second before the fuel pump is cut off. Like the ECM is doing it for some reason, or the ECM or some other critical piece is losing power.

I did plug into the OBD port and the sensor plots and other readings looked normal. The only oddity was that the long-term fuel trim was 5.5% and 6.0% bank 1/bank 2.

Whatever it is, it's starting to happen more often.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe