FuelFacts

← all 1984 Pontiac Bonneville trims

1984 Pontiac Bonneville — 5.7L 8-cyl, Automatic 3-spd

This 1984 Pontiac Bonneville (5.7L 8-cyl, Automatic 3-spd) runs on diesel. DIESEL

21
MPG combined (18 city / 25 hwy)
$3,414
est. fuel cost / year (today’s prices, 15k mi)
tailpipe CO₂

At today's AAA national average price ($4.78/gal, 2026-07-05) — the EPA's own price/date assumption isn't exposed in the public dataset, so we recompute this from the EPA's MPG figure and a sourced current price.

This 1984 model was originally EPA-tested under the pre-2008 2-cycle method, which didn't account for highway speeds over 60 mph, air-conditioner use, or cold starts. When EPA overhauled the test for model year 2008, city ratings fell by about 12% and highway by about 8% on average industry-wide — and EPA retroactively adjusted every 1984-2007 rating to the stricter standard so old and new cars could be compared fairly. The MPG above is already on that modern scale — the window sticker on this car when it was new likely showed a higher, pre-2008-method number.

Other 1984 Pontiac Bonneville trims

TrimFuelMPGFuel/yr
3.8L 6-cyl, Automatic 3-spdREGULAR19$3,000
3.8L 6-cyl, Automatic 3-spdREGULAR18$3,167
5.0L 8-cyl, Automatic 4-spdREGULAR17$3,353
5.0L 8-cyl, Automatic 4-spdREGULAR17$3,353
5.0L 8-cyl, Automatic 3-spdREGULAR16$3,562
5.0L 8-cyl, Automatic 3-spdREGULAR15$3,800
5.7L 8-cyl, Automatic 4-spdDIESEL21$3,414

EPA fuel type: Diesel · class: Midsize Cars · engine: 5.7L 8-cyl · transmission: Automatic 3-spd · MPG retrieved 2026-07-24.