Shop 4.0L
Ripp Hi-Perf Coil Pack Kit w/ Spark Plug Wires & NGK Plugs: Jeep Grand Cherokee 4.0L (99-04)
Ripp
Regular price from $299.00 Sale
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DiabloSport inTune i3 Platinum Programmer: Jeep Grand Cherokee / Wrangler / Commander 2005-2014
Diablo Sport
Regular price
$535.95
$499.95
Sale
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Amerihood AAG Functional Ram Air Hood: Jeep Wrangler TJ 1997 - 2006
Amerihood
Regular price
$986.00
$655.00
Sale
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DiabloSport Trinity 2 (T2 EX) Platinum Programmer / Monitor: Jeep 2005-2014
Diablo Sport
Regular price
$787.95
$673.95
Sale
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DiabloSport inTune i3 Programmer: Jeep Grand Cherokee / Wrangler / Commander 2005-2014 5.7L Hemi / 4.0L I6
Diablo Sport
Regular price
$535.95
$499.95
Sale
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Edge Digital Monitor Insight CTS3: Fits Most Domestic Gas and Diesel Trucks 1996-2024 w/ Windshield Mounting Bracket
Edge
Regular price
$575.95
$549.95
Sale
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Amerihood GTR Functional Ram Air Hood: Jeep Grand Cherokee 1999 - 2004
Amerihood
Regular price
$687.46
$530.68
Sale
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Mishimoto 25 Row Oil Cooler Non-Thermostatic: UNIVERSAL Silver
Mishimoto
Regular price
$504.00
$457.95
Sale
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MagnaFlow BRE Direct-Fit Aluminized Steel Exhaust Kit: Jeep Grand Cherokee 99-04
Magnaflow
$238.00
- Unit price
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Spec D Projector Halo Headlights (Smoke): Jeep Grand Cherokee 1999 - 2004
Spec D
Regular price
$217.00
$161.00
Sale
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Spec D Aluminum Radiator: Jeep Grand Cherokee 4.0L w/ Automatic Transmission 1999 - 2004
Spec D
Regular price
$274.00
$203.00
Sale
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DiabloSport Trinity 2 (T2 EX) Programmer / Monitor: Jeep 2005-2014
Diablo Sport
Regular price
$806.95
$673.95
Sale
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Spec D LED Projector HeadLights (Black): Jeep Grand Cherokee 1999 - 2004
Spec D
Regular price
$213.00
$158.00
Sale
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Crown Auto Front Control Arm Kit: Jeep Wrangler / Cherokee / Comanche 1984-2006
Crown Auto
$169.40
- Unit price
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Crown Auto Auto Trans Oil Pan Kit 42RLE: Fits Jeep Wrangler / Liberty 2003-2012 w/ 3.8L / 4.0L
Crown Auto
$115.50
- Unit price
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Crown Auto Transmission Pan 42RLE: Jeep Wrangler JK / TJ 2003-2011 / Liberty KJ KK 2003-2012
Crown Auto
$73.82
- Unit price
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Crown Auto Ball Joint Set Upper & Lower (FRONT/REAR): Jeep Wrangler JK 2007-2018 3.6L / Jeep Grand Cherokee 1999-2004 4.0L / 4.7L V8
Crown Auto
$73.15
- Unit price
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Crown Auto Front Diff Carrier Bearing Set: Fits Jeep / Dodge 1997-1999
Crown Auto
$69.30
- Unit price
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Crown Auto Aluminum Heater Core Plastic Tanks: Jeep Wrangler 2002-2005 LHD
Crown Auto
$148.22
- Unit price
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Crown Auto Cabin Air Filter Kit w/ Door & Retainers: Jeep Grand Cherokee 1999-2010 3.7L/4.7L
Crown Auto
$75.08
- Unit price
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Crown Auto HD 760 Series Front Axle U-Joint: Fits Jeep Wrangler / Grand Cherokee 1991-2012
Crown Auto
$73.15
- Unit price
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Crown Auto Rear Axle Shaft Bearing Kit: Jeep Wrangler JK 1997-2018
Crown Auto
$69.30
- Unit price
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Crown Auto Transfer Case Switch: Fits Jeep Wrangler / Gladiator / Grand Cherokee 2002-2025
Crown Auto
$61.60
- Unit price
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Winjet Replacement Fog Light Clear: Jeep Grand Cherokee 1999-2003
Winjet
Regular price
$42.99
$38.69
Sale
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Winjet LED Tail Light Black/Smoke: Jeep Grand Cherokee 1993-1998
Winjet
Regular price
$138.99
$125.09
Sale
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Nitrous Express All Dodge EFI Single Nozzle Nitrous Kit Stage 1: Fits Dodge/Jeep/Chrysler 1992-2005 2.5L-4.0L
Nitrous Express
$781.77
- Unit price
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RockJock Front Coil Springs 2in Lift 3in Lift JK 2D (FRONT): Jeep Wrangler TJ/LJ/JK 1997-2018
RockJock
$284.00
- Unit price
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RockJock Front Coil Springs 4in/5in Lift (F&R): Jeep Wrangler 1997-2018 2.5L/4.0L/3.6L V6
RockJock
$284.00
- Unit price
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RockJock Johnny Joint Uni-Ball Front Diff 5/8in Thru-Bolt: Fits Jeep 1993-2026
RockJock
$173.00
- Unit price
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Exedy Stage 1 Organic Clutch: Dodge Dakota / Jeep Wrangler 1992-2011 3.8L-4.0L V6/I6
Exedy
Regular price
$533.37
$453.35
Sale
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Nitrous Express EFI Single Nozzle Nitrous Kit 15lb Bottle: Fits Dodge / Jeep 1992-2005 2.5L/3.9L V6
Nitrous Express
$1,017.64
- Unit price
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Nitrous Express EFI Single Nozzle Nitrous Kit Composite Bottle: Fits Dodge / Jeep 1992-2005 2.5L/3.9L V6
Nitrous Express
$1,759.79
- Unit price
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Eaton Master Install Kit (FRONT): Fits Jeep Wrangler / Grand Cherokee 1991-2014 2.5L-6.4L
Eaton
Regular price
$205.98
$176.99
Sale
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Nitrous Express EFI Single Nozzle Nitrous Kit 35-150HP w/10lb Bottle: Fits Dodge 1992-2005
Nitrous Express
$918.25
- Unit price
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Nitrous Express EFI Single Nozzle Nitrous Kit 35-150HP w/5lb Bottle: Fits Dodge 1992-2005
Nitrous Express
$905.00
- Unit price
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Skyjacker Manual Trans Shifter Relocation Bracket: Jeep Wrangler 1997-2016 2.5L I4 / 3.6L V6 / 3.8L V6 / 4.0L I6
Skyjacker
$98.92
- Unit price
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Raxiom Axial 7-In LED Headlights DRL Black Housing: Jeep Wrangler 1997-2018 4.0L I6 / 3.8L V6 / 3.6L V6 - Clear Lens
Raxiom
$139.99
- Unit price
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Performance Upgrades for Your 4.0L Inline-Six Engine
The 4.0L inline-six engine is a durable and smooth-running powerplant widely recognized in Jeep Wrangler and Cherokee models. Known for its reliability and balanced power delivery, this engine offers a solid base for bolt-on performance enhancements that improve throttle response and efficiency without sacrificing longevity.
Key Performance Upgrades for the 4.0L Engine
Enhancing your 4.0L engine focuses on improving airflow, ignition, and engine management to unlock better throttle response and overall drivability. Popular upgrades include high-flow intake systems that increase air volume, performance exhaust components that reduce backpressure, and ignition upgrades that ensure stronger, more consistent sparks.
- High-flow air intake systems to boost airflow and efficiency
- Performance exhaust components for improved scavenging and sound
- Ignition and spark upgrades to optimize combustion
- Engine management and tuning tools for precise calibration
How to Maintain Reliability While Upgrading Your 4.0L
The 4.0L engine’s reputation for durability means upgrades should complement its robust design without over-stressing components. Focus on bolt-on parts that enhance performance within the engine’s mechanical limits. Proper tuning and quality parts help maintain reliability while extracting more capability from your engine.
Find the Right 4.0L Engine Parts at FastHemis
At FastHemis, we offer a curated selection of 4.0L engine upgrades designed to improve performance and maintain reliability. Whether you’re looking for intake kits, exhaust solutions, ignition components, or tuning accessories, our parts are fitment-focused and engineered for your Jeep’s inline-six. Shop the 4.0L collection today to enhance your engine’s capability.