P0358

P0358 is the cylinder 8 ignition coil primary/secondary circuit fault — V8 (or larger). Cylinder 8 location: on Ford Modular V8 it's the rear cylinder of bank 2 (driver side, against the firewall), on GM LS V8 it's the rear cylinder of bank 2 (passenger side, against the firewall), on Chrysler Hemi it's the rear of bank 2 (passenger side), on BMW V8 it's bank 2 rear, on Mercedes V8 it's bank 2 rear. Cheapest-first diagnostic: swap the cylinder 8 coil with a known-good front-bank coil, clear codes, drive cycle. Code moves = $35-$150 coil swap. Code stays at cylinder 8 = trigger wire integrity (under 0.5 ohms ECM to coil), B+ feed check (12.0-12.6V static / 13.5-14.5V running), ground drop check (under 0.1V under load). Scope the trigger pulse. Cylinder 8 is almost always the most thermally abused coil on the engine — rear of the rear bank, packed against the firewall, sitting on top of the exhaust manifold heat plume — so coil failure here typically signals the rest of the set is within weeks of failing. On Ford 5.4L 3V and GM LS truck V8s, replace the full set if any one cylinder-7/8 coil fails on a high-mileage example; the labor to do them individually as they fail adds up to more than a complete set replacement.

Vehicle-specific patterns: 2004-2010 Ford 5.4L 3V cylinder 8 P0358 is the most thermally abused position on the Triton — driver bank rear under the cowl, TSB 08-7-6 coil/boot kit, and the cylinder 8 plug is the most likely to break off in the head if seized; budget for the Lisle 65600 broken-plug extractor and possibly head-off repair on early 2004 trucks ($30-$2,000 depending on how badly it breaks). 2005-2013 GM 5.3L/6.0L LS truck cylinder 8 P0358 from D585 failure, swap to D514A. 2009-2015 Cadillac CTS-V 6.2L LSA supercharged cylinder 8 P0358 from heat-soak — supercharged LS coils need OE GM part numbers, aftermarket fails fast. 2003-2010 Hemi 5.7L cylinder 8 P0358 (passenger bank rear) from boot crack and harness chafing on exhaust crossover. 2008-2014 BMW N63 twin-turbo V8 cylinder 8 P0358 — same N63 service action package applies; the turbos sit right next to bank 2 and cook coils 5-8. 2007-2014 Lexus LS460/IS-F 5.0L 2UR-GSE cylinder 8 P0358 — Denso COP, OE only, and on the IS-F the rear coils need intake removal for proper access. Estimated repair: $35 (one coil) to $5,200 (broken plug + coil + head work on 5.4L 3V).