Engine, 3.8L (231 cu in) V6, sequential fuel injection

Starfire V8 option (dropped during 1979)

VIN code 3; multi-port injection 125 hp in 1984–1985, sequential injection 150 hp in 1986–1988, the figures Wikipedia's Ciera table gives; Wikipedia's Buick V6 article lists the Ciera 1984–1988 under its combined LG2/LG3 heading (a slash form, which names neither code) and gives LG3 to VIN code 3 at those outputs, while the Ciera table prints LG2 for the same years and the Ciera infobox labels the engine LG3: a same-year conflict between two codes; sibling gnttype.org Buick VIN table prints LG3 for the 1987 Buick Century (Buick only, used as corroboration)

150 hp, the optional engine in 1986 and the only engine in 1987 and early 1988; Wikipedia's Oldsmobile 88 engine table is headed RPO/VIN code and prints "LG3/3" for 1986 to mid-1988 (the LN3 replaced it that year, so the two codes overlap in 1988), which pairs the code with a VIN digit and is not a slash form of two codes; shared H-body code, corroborated from the Buick LeSabre: gnttype.org's 1986 and 1987 Buick VIN tables each print engine option code LG3 for the LeSabre (one source, as the two blocks print the same engine cell); the 1986 NICB Oldsmobile engine table prints VIN letter B for the 3.8L V6 fuel-injected engine, where Wikipedia and gnttype.org give VIN 3 (the Buick figure)

VIN code 3; optional in 1985, multiport injection, 125 hp, sequential from 1986, 150 hp in 1987 (Wikipedia's Ninety-Eight article, which gives 140 hp for 1986); Wikipedia's Buick V6 article lists the 1985–1987 Ninety-Eight among the 3.8 FWD engine's applications under a combined LG2/LG3 heading, which names neither code, and gives 125 hp to the pre-1986 engine and VIN code 3 (the LG3) to the 150 hp engine; 1986 is left out because the car's 140 hp matches the article's LG2 line while the sibling gnttype.org Buick Electra block prints LG3 for 1986, a same-year conflict between codes left unsettled; shared C-body code: gnttype.org's 1986 and 1987 Buick VIN tables print LG3 for the Electra (cited from the Buick Electra; its 1985 Electra block is a copy of its 1986 block and is not used), but no source dates the code on an Oldsmobile besides Wikipedia, so the row stays single-source; 1988 is left out because Wikipedia's Buick V6 article ends the Ninety-Eight's list at 1987

shared E-body code; cited from the Buick Riviera: gnttype.org's 1987 Buick VIN table prints LG3 (VIN code 3, 3.8L V6 SFI) for the Riviera Luxury, and Wikipedia's Buick V6 article names the Riviera's 1987 engine LG3; for the Toronado that article lists it only in a block shared by two engine codes, headed by LG2 and LG3, so no code is claimed for 1986; no Oldsmobile-specific source prints the code; a Wikipedia slash form is not a per-year reading