Chevrolet Vortec 4.3 V6 (L35 / LB4 / LV3)

GM's 4.3 V6 — a small-block V8 with two cylinders removed, which is not a figure of speech: the bore, stroke and much of the parts bin are shared with the 350. In the S-10, Sonoma, Blazer, Caprice and, in its modern form, the Silverado and Sierra.

Its defining fault belongs to the central-port-injected engines of 1996–2002, and it is the spider. A single injector assembly sits under the intake manifold and feeds six nylon lines to poppet nozzles at each port. The lines split and the poppets stick, and the result is hard starting, a rich-running misfire and a fuel smell — diagnosed for months as ignition, because everything upstream reads normal. On a 4.3 of those years, hard hot starting with a strong fuel smell is the spider until proven otherwise, and the intake has to come off to see it.

The distributor is the other recurring item on that generation: its shaft bushing wears and the timing wanders, producing a stumble that follows engine temperature.

The family also shares the GM-wide intake manifold gasket, and the modern LV3 shares nothing of the spider — it is direct-injected with cylinder deactivation, and its faults are the Gen V small block's.