FuelFacts

2004 Ford Mustang MPG & Specs — Real-World vs EPA, All Trims

Every trim takes regular — no premium needed.

17–21
MPG combined (15–18 city / 21–27 hwy)
$2,714–$3,353
est. fuel / year (today's prices, 15k mi)
Regular
gas type

Is the 2004 Ford Mustang good on gas?

At up to 21 MPG combined, the 2004 Ford Mustang is worse than average for a Subcompact Cars — that class averages about 22.8 MPG across 5,756 EPA-tested versions, so it's on the thirsty side for its size.

Real-world MPG vs the EPA number

The EPA figures above come from a standardized dynamometer test, not the open road — real-world MPG typically runs a bit lower depending on your driving, climate and terrain. That's true of every car on this site, old or new.

This 2004 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.

At today's AAA national average price — $3.80/gal for regular gas as of 2026-07-05 — the most efficient trim runs about $2,714/year (roughly $226/month, about $18.10 per 100 miles) at the EPA's assumed 15,000 miles/year, using an estimated 714 gallons a year. We don't estimate a cost-per-fill since exact tank size isn't in the public EPA dataset, but the per-100-mile figure scales to any tank. Current national average gas prices →

2004 Ford Mustang trims & fuel economy

Trim (engine / transmission)FuelMPGFuel/yr (today's price)
3.8L 6-cyl, 5-spd manual, RWDREGULAR21$2,714
3.9L 6-cyl, 5-spd manual, RWDREGULAR21$2,714
3.8L 6-cyl, Automatic 4-spd, RWDREGULAR20$2,850
3.9L 6-cyl, Automatic 4-spd, RWDREGULAR20$2,850
4.6L 8-cyl, Automatic 4-spd, RWDREGULAR18$3,167
4.6L 8-cyl, 5-spd manual, RWDREGULAR18$3,167
4.6L 8-cyl, 5-spd manual, RWDREGULAR18$3,167
4.6L 8-cyl, Automatic 4-spd, RWDREGULAR17$3,353
4.6L 8-cyl, 6-spd manual, RWDREGULAR17$3,353

2004 Ford Mustang specs

What the EPA test-car listings record for this model year — every combination sold is a row in the trims table above.

Engine options3.8L 6-cyl · 3.9L 6-cyl · 4.6L 8-cyl
Transmission5-spd manual · Automatic 4-spd · 6-spd manual
Drive typeRWD
EPA body classSubcompact Cars
FuelRegular

Other years of the Ford Mustang

2008 Ford Mustang2007 Ford Mustang2006 Ford Mustang2005 Ford Mustang2003 Ford Mustang2002 Ford Mustang2001 Ford Mustang2000 Ford Mustang

Similar cars (Subcompact Cars)

2004 Chevrolet Cavalier Dual-fuel2004 Volkswagen R322004 Maserati Coupe Cambiocorsa/Coupe GT2005 Toyota Celica2003 Ford Escort ZX22003 Toyota Camry Solara Convertible

Cars that take premium · Cheapest cars to fuel · Where fuel grade depends on the trim · Fuel guides

9 trim(s) · EPA FuelEconomy.gov data retrieved 2026-08-01 · fuel prices AAA national average as of 2026-07-05.