1992 Jeep Comanche Problems: 3 Issues Every Owner Should Know

1992 model year · 400+ owner reports · Updated May 2026

According to Au7o's analysis of 400+ owner reports, the 1992 Jeep Comanche has 3 documented known issues, with 1 rated critical. The most serious is Floor Pan and Frame Rust-Through ($300-$4,000 repair). The most commonly reported issue is Floor Pan and Frame Rust-Through with 220 owner reports. Across all issues, repair costs range from $150 to $4,000. DIY maintenance guides at au7o.io.

All 3 Known Issues

Community Reported

220 owners

On the 1990-1992 Jeep Comanche, the Jeep Comanche (MJ platform) is extremely susceptible to floor pan and frame rust, especially in salt-belt states. The driver and passenger foot wells, rear cab corners, and bed floor are the primary rust-through areas. The unibody construction means that floor pan rust is structural and affects vehicle safety. Water intrusion through deteriorated door and window seals accelerates the corrosion. Many surviving Comanches have been lost to rust rather than mechanical failure. Rust repair requires cutting out affected sections and welding in new metal patches.

Common Symptoms

Visible rust holes in floor pans
Water intrusion into cabin during rain
Soft or spongy floor when pressed
Rust bubbling under paint on cab corners and rocker panels
Structural weakness visible during inspection

How to Fix

Inspect the entire cab floor, rocker panels, cab corners, rear frame sections, leaf-spring/shackle mounts, and bed supports by removing carpet and undercoating, then probe all suspect areas with a pick or hammer to identify thin metal and hidden perforation. Any rust-through or heavily scaled structural metal should be cut back to solid steel and repaired with welded replacement floor pans, patch panels, or fabricated 16-18 gauge steel sections; treat surrounding areas with rust converter or epoxy primer, seam sealer, cavity wax, and replace leaking door/window seals to stop future water intrusion. If the frame rails, spring mounts, or major unibody sections are severely compromised, professional structural repair or donor-section replacement is required, and some trucks may be uneconomical to save. Typical costs range from about $500-$1,500 for localized patch repairs to $3,000-$8,000+ for extensive floor, cab corner, and structural rust restoration.

What Owners Are Using

Parts and tips from 220+ owners who fixed this issue

Tip
Tip
UpgradePOR-15 rust preventive coating stops rust permanently (POR-15 Rust Preventive Coating)
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UpgradeRust-Oleum rust converter spray for treating corroded panels (Rust-Oleum Rust Converter Spray)
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UpgradeDorman weatherstrip seal prevents water leaks and wind noise (Dorman Weatherstrip Seal)
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Upgrade3M Super Weatherstrip Adhesive for reattaching loose seals (3M Weatherstrip Adhesive)
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Typical repair cost:$300 - $4,000

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220+ owners have reported this issue

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Community Reported

High Confidence220 reportsLast reported by owners Feb 2026Reviewed Feb 2026

Community Reported

180 owners

On the 1990-1992 Jeep Comanche 4.0L Inline-6, the cast iron exhaust manifold on the 4.0L AMC/Jeep inline-6 engine is prone to cracking from thermal stress cycling. The manifold design does not accommodate thermal expansion well, and cracks develop between the exhaust ports, typically between cylinders 3-4 or 5-6. Cracked manifolds cause exhaust leaks that are loudest on cold startup and may quiet down as the manifold expands when hot. The exhaust leak can cause a ticking or hissing sound that is often mistaken for a lifter or valve issue. Broken exhaust manifold bolts are extremely common and can complicate the repair.

This issue also affects: BMW X6, Chevrolet Equinox, Chrysler 200

Common Symptoms

Ticking or hissing exhaust leak noise, loudest on cold startup
Exhaust smell in engine bay or cabin
Reduced engine performance
Check engine light with catalyst efficiency codes
Noise diminishes as engine warms up

How to Fix

What Owners Are Using

Parts and tips from 180+ owners who fixed this issue

Tip
Tip
UpgradeExhaust manifold gasket set seals exhaust leaks at the head (Fel-Pro Exhaust Manifold Gasket Set)
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UpgradeExhaust manifold stud kit replaces broken or corroded studs (Dorman Exhaust Manifold Stud Kit)
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Typical repair cost:$200 - $700

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180+ owners have reported this issue

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Community Reported

High Confidence180 reportsLast reported by owners Feb 2026Reviewed Feb 2026

On the 1990-1992 Jeep Comanche 4.0L, the 1990 Comanche with the 4.0L uses the Renix (Renault/Bendix) fuel injection system, which is less reliable than the later Chrysler MPFI system used from 1991+. The Renix system relies on several sensors that fail with age: the coolant temperature sensor (CTS), throttle position sensor (TPS), and manifold absolute pressure (MAP) sensor. Failed sensors cause hard starting, rough idle, poor fuel economy, and stalling. The wiring harness connectors also corrode, causing intermittent issues that mimic sensor failure.

Common Symptoms

Hard starting especially when cold
Rough or hunting idle
Stalling when coming to a stop
Poor fuel economy (under 15 mpg)
Hesitation or stumble during acceleration
Check engine light intermittently

How to Fix

Replace the CTS, TPS, and MAP sensors as a set — they are inexpensive and the labor overlaps. Clean all wiring harness connectors with electrical contact cleaner and apply dielectric grease. For 1990 models, consider upgrading to the 1991+ Chrysler MPFI system (often called a "Renix to HO swap") which uses a more reliable ECU and simplified sensor array. Replace the O2 sensor at the same time.

What Owners Are Using

Parts and tips from 0+ owners who fixed this issue

Tip
UpgradeBosch fuel injector set — OEM replacement for precise fuel delivery (Bosch Fuel Injector)
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UpgradeChevron Techron fuel injector cleaner — restores injector flow (Chevron Techron Fuel Injector Cleaner)
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Typical repair cost:$150 - $500

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Community Reported

Medium Confidence0 reportsLast reported by owners Invalid DateReviewed Invalid Date

Frequently Asked Questions

What are the most common Jeep Comanche problems?

According to Au7o's analysis of 400+ owner reports, the 1992-1992 Jeep Comanche has 3 documented issues. The most frequently reported are: Floor Pan and Frame Rust-Through, 4.0L Inline-6 Exhaust Manifold Cracking, Renix Fuel Injection System Sensor Failures. Of these, 1 is rated critical and should be addressed promptly.

Is the Jeep Comanche reliable?

The 1992-1992 Jeep Comanche has 3 known issues documented across 400+ owner reports. 1 issue is rated critical: Floor Pan and Frame Rust-Through. Prospective buyers should inspect for these issues and factor potential repair costs into their purchase decision. Regular maintenance following the manufacturer's schedule helps prevent many common problems.

How much does it cost to fix common Jeep Comanche problems?

Repair costs for known Jeep Comanche issues range from $150 to $4,000, depending on the specific problem and whether you choose DIY or professional repair. The most critical issue, Floor Pan and Frame Rust-Through, typically costs $300-$4,000 to repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.

What is the 1990-1992 Jeep Comanche Floor Pan and Frame Rust-Through?

The Jeep Comanche (MJ platform) is extremely susceptible to floor pan and frame rust, especially in salt-belt states. The driver and passenger foot wells, rear cab corners, and bed floor are the primary rust-through areas. The unibody construction means that floor pan rust is str… Repairs typically run $300-$4,000. Severity: high.

What is the 1990-1992 Jeep Comanche 4.0L Inline-6 Exhaust Manifold Cracking?

The cast iron exhaust manifold on the 4.0L AMC/Jeep inline-6 engine is prone to cracking from thermal stress cycling. The manifold design does not accommodate thermal expansion well, and cracks develop between the exhaust ports, typically between cylinders 3-4 or 5-6. Cracked man… Repairs typically run $200-$700. Severity: medium.

What is the 1990-1992 Jeep Comanche Renix Fuel Injection System Sensor Failures?

The 1990 Comanche with the 4.0L uses the Renix (Renault/Bendix) fuel injection system, which is less reliable than the later Chrysler MPFI system used from 1991+. The Renix system relies on several sensors that fail with age: the coolant temperature sensor (CTS), throttle positio… Repairs typically run $150-$500. Severity: medium.

1992 Jeep Comanche Problems: 3 Issues Every Owner Should Know

All 3 Known Issues

1990-1992 Jeep Comanche: Floor Pan and Frame Rust-Through#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

1990-1992 Jeep Comanche: 4.0L Inline-6 Exhaust Manifold Cracking#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

1990-1992 Jeep Comanche: Renix Fuel Injection System Sensor Failures#

Common Symptoms

How to Fix

What Owners Are Using

Research This Issue

Other Jeep Models

Frequently Asked Questions

What are the most common Jeep Comanche problems?

Is the Jeep Comanche reliable?

How much does it cost to fix common Jeep Comanche problems?

What is the 1990-1992 Jeep Comanche Floor Pan and Frame Rust-Through?

What is the 1990-1992 Jeep Comanche 4.0L Inline-6 Exhaust Manifold Cracking?

What is the 1990-1992 Jeep Comanche Renix Fuel Injection System Sensor Failures?