Car Model History

Third generation · Fox-body · 1979–1993

1991Ford Mustang

The long-running Fox-body, built on Ford’s Fox platform from 1979 to 1993.

Third generation · Fox-body

1991 Ford Mustang (Fox-body) — green LX 5.0 coupe, right side profile

Photo: TJKula / Wikimedia Commons, licensed under CC BY 4.0. Cropped to 16:9.

Quick facts

Engines
2offered2.3 I4 (dual-plug, fuel-injected) → 302 "5.0 HO" V8 (mass-air)
Top output
225hp302 "5.0 HO" V8 (mass-air)
Production
90,385units

Body stylesCoupe (notchback, LX) · Hatchback (3-door) · Convertible

Start here

What do you need to know?

This page covers the whole 1991 Ford Mustang model year. Choose your task first; exact trims and engines are separated where the factory offered different versions.

Documented lineup

Find your exact 1991 Mustang

Start with a family, body style, or engine. Every card opens the facts and maintenance information for that factory version.

16factory configurations
Exact factory pairings documentedHow this lineup was verified

These source-backed records identify published body, engine, and transmission combinations. Exact pairings do not by themselves assert that every factory option or special edition is represented.

16versions shown
Two-door sedan

LX Two-door sedan 5MT

Body
Two-door sedan
Engine
2.3L EFI inline-four
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Two-door sedan

LX Two-door sedan 4AT

Body
Two-door sedan
Engine
2.3L EFI inline-four
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Three-door hatchback

LX Three-door hatchback 5MT

Body
Three-door hatchback
Engine
2.3L EFI inline-four
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Three-door hatchback

LX Three-door hatchback 4AT

Body
Three-door hatchback
Engine
2.3L EFI inline-four
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Convertible

LX Convertible 5MT

Body
Convertible
Engine
2.3L EFI inline-four
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Convertible

LX Convertible 4AT

Body
Convertible
Engine
2.3L EFI inline-four
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Two-door sedan

LX 5.0L Two-door sedan 5MT

Body
Two-door sedan
Engine
5.0L High-Output EFI V8
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Two-door sedan

LX 5.0L Two-door sedan 4AT

Body
Two-door sedan
Engine
5.0L High-Output EFI V8
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Three-door hatchback

LX 5.0L Three-door hatchback 5MT

Body
Three-door hatchback
Engine
5.0L High-Output EFI V8
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Three-door hatchback

LX 5.0L Three-door hatchback 4AT

Body
Three-door hatchback
Engine
5.0L High-Output EFI V8
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Convertible

LX 5.0L Convertible 5MT

Body
Convertible
Engine
5.0L High-Output EFI V8
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Convertible

LX 5.0L Convertible 4AT

Body
Convertible
Engine
5.0L High-Output EFI V8
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Three-door hatchback

GT Three-door hatchback 5MT

Body
Three-door hatchback
Engine
5.0L High-Output EFI V8
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Three-door hatchback

GT Three-door hatchback 4AT

Body
Three-door hatchback
Engine
5.0L High-Output EFI V8
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version
Convertible

GT Convertible 5MT

Body
Convertible
Engine
5.0L High-Output EFI V8
Gearbox
5-speed manual overdrive
Built
Regular production
Open exact version
Convertible

GT Convertible 4AT

Body
Convertible
Engine
5.0L High-Output EFI V8
Gearbox
4-speed automatic overdrive
Built
Regular production
Open exact version

The 1991 model year

Overview

The four-cylinder finally got serious attention: a twin-spark-plug (dual-plug) 2.3 raised its rating to 105 hp. The 5.0 V8 carried over at 225 hp but now wore new 16-inch five-spoke alloy wheels with directional 'pizza-cutter' styling. This was the first year a base Mustang crossed $10,000. (Horsepower figures are SAE net.)

Specifications

Engines
  • 2.3 I4 (dual-plug, fuel-injected)105 hp
  • 302 "5.0 HO" V8 (mass-air)225 hp
Transmissions
5-speed manual (T-5), AOD 4-speed automatic
Body styles
Coupe (notchback, LX), Hatchback (3-door), Convertible
Production
90,385

Year over year

What changed

  • The 2.3 four gained a dual-spark-plug head, rising to 105 hp.
  • New 16-inch five-spoke directional alloy wheels for the V8 cars.
  • A revised convertible top mechanism.
  • A base Mustang topped $10,000 for the first time.

Worth knowing

Notable

  • The '5-lug' marketing aside, these remained four-lug cars; the new 16-inch five-spoke wheels are the visual marker of 1991–93 V8s.

Living with it

Reliability & ownership notes

  • The dual-plug 2.3 is smoother and a bit stronger than the earlier four.
  • Same durable 225-hp mass-air 5.0.
  • Inspect for Fox-body rust; sales were declining and some cars saw hard use.

Maintenance & service parts

Keep your 1991 Mustang on the road

Start with the service interval, then match the engine or exact version you own. Order links appear only when a catalog-backed part number is available, and every listing still needs a fitment check.

Service desk

What this car needs & when

Use this as a service-planning checklist for 1991 Ford Mustang. Start with the interval, confirm which engine or configuration you have, then use an exact ordering reference when one is verified.

Service topics
7
Factory intervals
6
Fitment-scoped
7
Exact references
1

Before orderingIdentify your engine, options and build date.Part numbers and sizes can change within one model year. Shopping links appear only for catalog-backed references; still verify the listing against your vehicle before ordering.

  • Engine oil and filter

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · US

    Published interval: 7,500 mi · normal service

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

    Severe service

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · US · Ford severe-service operating conditions

    Published interval: 3,000 mi · severe service

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

  • Engine oil filter

    Exact reference available

    Manufacturer application-catalog fitment only; this does not establish an oil-change interval.

    Applies to: 1991 · US

    2.3L EFI inline-four

    Baldwin B2

    Applies to: 1991 · 2.3L EFI inline-four · US

    Source: Baldwin Filters — Automotive Applications catalog (2017) · PDF page 260 — Ford 1991, Mustang 2.3L row · checked

    Verified ordering references

    5.0L High-Output EFI V8

    Baldwin B2

    Applies to: 1991 · 5.0L High-Output EFI V8 · US

    Source: Baldwin Filters — Automotive Applications catalog (2017) · PDF page 260 — Ford 1991, Mustang 5.0L row · checked

    Verified ordering references

  • Engine air-filter element

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · US

    Published interval: 30,000 mi

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

  • Engine coolant

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · US

    Published interval: 30,000 mi

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

  • Spark plugs (except platinum)

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · US

    Published interval: 30,000 mi

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

  • Crankcase ventilation filter

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4 · US

    Published interval: 30,000 mi

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

    5.0L HO V8 — PCV valve and crankcase filter

    Applies to: 1991 · 5.0L HO V8 · US

    Published interval: 15,000 mi

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

  • Automatic transmission fluid

    Sourced interval available

    Applies to: 1991 · 2.3L SOHC I4, 5.0L HO V8 · automatic · US · Ford severe-service operating conditions

    Published interval: 30,000 mi · severe service

    Source: Operation CHARM — 1991 Ford Mustang factory service schedule mirror · Normal Service 7,500/15,000/30,000-mile and Severe Service 3,000/30,000-mile records; 2.3L SOHC and 5.0L HO schedules cross-checked · checked

Collect

Bring this model year home

Find a scale model using the exact year, make, and model—not a generic generation search.

Sources

  1. Wikipedia — "Ford Mustang (third generation)"
  2. FoxStang — 5.0 Fox-body engine specs
  3. LMR (Late Model Restoration)

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