P0311

P0311 is a cylinder 11 misfire — this code only exists on V12 platforms (BMW N73/N74/M73, Mercedes M275/M279, Aston Martin AM11/AM29, Ferrari F140, Rolls-Royce N74), where cylinders 7-12 are the right bank. Diagnostic ladder is the same conceptually as on a V8 but mechanically harder: each bank has its own DME on most modern V12s, its own coil per cylinder, its own VANOS/CVVT actuator, and on direct-injected V12s like the N74, its own high-pressure fuel pump. Start by pulling the cylinder 11 coil and plug — inspect for fouling, swap coil with a known-good cylinder on the same bank, and re-run. If the misfire follows the coil, replace it (BMW N74 coils run $80-120 each; Ferrari F140 coils run $200-280). Check fuel pressure on bank 2 (high-pressure pump is bank-specific on N74); a failing HPFP starves the right bank under load and shows up first on cylinder 11 because of its position in the fuel rail. Caveat: on V12s the rear cylinders are nearly unreachable without partial intake removal — quote labor honestly because a 4-hour V12 misfire diagnosis is realistic.

Vehicle-specific patterns: BMW N73 V12 (760i E65/E66, 2003-2008) — index-12 injector failure on cylinder 11 is the signature; the original-spec injectors were recalled and updated to index-12. Use ISTA to read injector adaptation values; anything more than 0.4ms correction is failing. BMW N74 V12 (760Li F02, Rolls-Royce Ghost/Wraith, 2009-2019) — rod bearing wear pattern shows on cylinder 11/12 before catastrophic failure; oil analysis catching copper at 60K miles is the early warning. Mercedes M275 V12 biturbo (S600, CL600, SL600, 2003-2014) — turbo oil-feed line failure starves the right bank turbo bearing, causing oil ingestion into cylinder 11 intake. Ferrari 599 GTB F140 V12 (2006-2012) — coil and HT lead degradation on cylinder 11; access requires intake plenum removal. Estimated repair: $180 to $4,200.