Pontiac Bonneville — Eighth generation, H-body (FWD) (1987–1991)

The eighth-generation Bonneville was Pontiac's front-wheel-drive H-body four-door sedan for the 1987–1991 model years, built at Willow Run and then Wentzville (Wikipedia). The NICB VIN manuals print the car lines as the Bonneville (1987 only) and the Bonneville LE, SE and SSE. No GM order guide, data book, Heritage kit or service RPO list for this generation is in the archive, and no Chevrolet kit shares its platform, so only engine and transmission codes are listed: Wikipedia's Pontiac Bonneville article names and dates the engines, and the Bonneville Club's RPO code listing, an undated list for the 1987–2005 cars, prints the same codes with meanings. No source read dates an option, package, axle, paint or trim code to this generation, so none is listed.

Codes

Engines

Code	Description	Years	Models/Notes	Confidence
LG3	Engine, 3.8L V6, multiport fuel injection, high output	1987–1988	150 hp, the only engine at launch (VIN 3); Wikipedia's Bonneville infobox lists it for 1987–1988 and its Buick V6 engine article lists the Bonneville under LG3 for 1987 to early 1988 and says the LG3 was still available in some models after the LN3 arrived, while the Bonneville text says the LN3 replaced it for 1988, a mid-year changeover, so 1987–1988 is claimed and the two codes overlap in 1988; the Bonneville Club list prints the code and its meaning but no year; Wikipedia's infobox calls the fuel system SFI, the Bonneville Club list prints MFI	confirmed
LN3	Engine, 3.8L V6, multiport fuel injection, 3800	1988–1991	the revised 3.8 L, 165 hp, sold as the 3800 V6 (VIN C); Wikipedia's infobox gives multiport injection and its text says sequential-port, the Bonneville Club list prints MFI and "3800 I"; the Bonneville Club list prints the code but no year	confirmed

Transmissions

Code	Description	Years	Models/Notes	Confidence
ME9	Transmission, 4 speed automatic, THM440-T4	1987–1991	matched to the unit by meaning: Wikipedia's infobox names the THM440T4 four-speed automatic for the whole generation (its text calls it the 4T60) but prints no code, and the Bonneville Club list, which has no year, prints ME9 with "THM440-T4"	single-source

Sources

Factory documents (T1)

No Pontiac factory document for the 1987–1991 Bonneville is in docs/factory-docs/ or docs/heritage-ocr/, the brief lists no Heritage kit, and no Chevrolet kit shares the H-body, so no row carries an [FD] or [HK] citation.

Other sources

https://en.wikipedia.org/wiki/Pontiac_Bonneville — eighth-generation infobox (engines with RPO and VIN codes, transmission, platform, plants), text and production table (retrieved 2026-11-05 as wikitext, action=raw)
https://en.wikipedia.org/wiki/Buick_V6_engine — application lists dating the Bonneville's LG3 and LN3 (retrieved 2026-11-05 as wikitext; a second Wikipedia article, read as a cross-check and not counted as independent)
https://www.gmforum.com/howto/BC/RPO%20code%20listing.php.htm — Bonneville Club, RPO code listing for all Bonneville years "87-05" (T3; undated, used for the codes and their meanings only; retrieved 2026-11-05 by direct fetch, no block)
NICB Passenger Vehicle Identification Manual, GM sections (T4): docs/reference/nicb/nicb1987-gm.txt p. 77 and nicb1991-gm.txt p. 38, read on the page images — Pontiac car lines Bonneville, Bonneville LE, SE and SSE and their VIN position 4–5 series codes by year