Buyer's Guide

The aim of this article is to allow you to make an informed purchase decision on a GTO, 3000GT or Stealth.

General Vehicle Items

This section contains items that should be investigated on any vehicle, and is good knowledge for any prospective vehicle buyer.


Ideally, the motor will start, run and idle. It shouldn't stutter or die, even when started cold.

Motors need lubrication in order to function correctly for any amount of time. Ideally, the seller should have records of motor oil changes. Synthetic oil is best, but costs more, so some people cheap out on it.

The type of gasoline that is used can also affect a motor's longevity. Modern motors will deal with the lower grade 87 gasoline, but older motors, especially high performance ones, usually prefer the better quality gasoline.


When you go out for a test drive, the transmission should shift smoothly, whether manual or automatic. If the gears grind when changing, it is hard to put the vehicle into gear, or it doesn't go into gear at all, this could indicate a number of issues (moreso on this platform).

Like motors, transmissions need lubrication in order to continue to function correctly. Ideally, the seller should have records of transmission oil changes. Transmission oil is changed less frequently than motor oil, so if the seller hasn't owned the vehicle for long, they may not have records of when it was changed.

Paint / Interior

Everyone likes a vehicle that looks nice. The paint on a vehicle can be blasted by wind, dirt and road debris, and the interior often wears out over many entrances and exits from the vehicle.

The driver's seat is typically the first part of the interior to show wear, along with the handbrake and shift knob of a manual transmission vehicle.

As for paint, common areas for damage are near the road, where rocks and other debris can make contact more easily, and under the gas door where lazy owners often let the gas cap dangle.

Rust is also a factor, though more common in some areas of the world than others. The easiest spot to check for rust is on the fuel sender cover, located on the right side of the trunk floor, beneath the spare tire. This is usually a decent indicator as to whether hidden rust can be found, such as under side skirts. Be sure to also look under the car and examine the area under the driver and passenger's feet, as rain and melted snow from the occupants' feet will pool in the carpet and cause rust through the floor.

On low vehicles, inspect under the front bumper for bottom-out damage. This damage occurs when a driver tries to take an incline (driveway, etc) that is too steep directly rather than at an angle.

Tires / Rims

Wheels and tires are a high-cost item, especially fancy rims and performance tires.

Before purchasing any vehicle, you should inspect how much tread is left on the tires, and if they are showing any signs of cracking. If the vehicle has been sitting for a long time, the tires may be flat. You should try to inflate them and ensure they hold air.

Rims are a common damage point as they can be bent by potholes in the road, or rashed by parking too close to a curb. Inspect the outer lip of the rim for any imperfections, as bends can stop the wheels from being balanced in the future, and lead to replacement. While curb rash is ugly, it does not typically pose a hazard to the driver.


The suspension is what absorbs impacts from imperfections in the road and can lead to decreased ride comfort or danger if not well maintained.

The simplest way to check the suspension of a vehicle is to push down on the body of the vehicle above the suspension and note whether the "shock" is absorbed. If the shocks are failing, the vehicle will likely bounce multiple times.

3S Specific Items

This section contains items that should be investigated on a 3S that do not typically apply to other vehicles.

Neglected 60k/120k Maintenance

If the previous owner cannot provide you with proof of when this service was done, and what parts were used, you should account for a 7-10h job for a first timer, or to pay a shop $800-$1600 USD in your negotiations.

If proof is not provided, assume this service is past due. It is absoluately necessary to ensure the longevity of your engine and cannot be ignored. Failing to perform this service will result in critical damage to your valves and potentially pistons, which will require motor rebuild or replacement.

The service needs to be done every 60,000 miles (hence the name, equivalent to 100,000 kilometers), or 5 years, whichever comes first.

Electronic Capacitors (Applies to 1991-1993, All Models)

Mitsubishi, like many manufacturers, used a electrolytic capacitors in their first generation 3S electronics that nowadays have long exceeded their expected lifespan.

This applies to every electical component in the vehicles, including the engine control unit (ECU), transmission control unit (TCU) on automatic vehicles, electronically controlled suspension computer (ECS) on equipped vehicles, digital climate control (DCC) on equipped vehicles, and other small controllers with capacitors such as some instrument cluster items.

For more information, see our guide on first generation electronics maintenance.

Ideally, you would want the electronics in your first generation vehicle to be refreshed.

Symptoms of a failing ECU could include any number of things as it controls the engine. The easiest way to diagnose a faulty ECU is to inspect it, but that isn't practical during a pre-purchase inspection. If the vehicle appears to run normally, this shouldn't be an immediate concern, but if they owner doesn't know the current status, it can be a bargaining point and should be investigated after purchasing.

18 Spline Transfer Shaft Failure (Applies to 1991-Mid 1992, Turbo Models)

The early models had an output/transfer shaft with 18 splines. While typically fine under normal load, they are less tollerant of additional power than the later 25 spline transfer shafts.

If you are buying a stock car and plan to keep it stock, this is likely not a concern for you. However, know that they are worth a little bit less than their later first-gen bretheren.

If the car was built after November 1991, it should have a 25 spline setup. If it was built before November 1991, it should have an 18 spline setup. If it was built in November, it's more likely to have 18 spline at the start of November, and more likely to have 25 spline at the end of November.

During a pre-purchase inspection, you can check for this by inspecting the build date on the sticker on the driver's side doorsill.

The "Free Boost" / "Boost Pill" Mod (Applies to 1991-1993, Turbo Models)

The "Free Boost" mod is misinformation that recommends removing a restrictor in the factory boost solenoid on first generation cars that is designed to limit boost spikes, in order to bring them up to second generation horsepower levels.

I would consider vehicles with their factory restrictor in place to be worth slightly more.

During a pre-purchase inspection, you can check for this by inspecting the boost solenoid and seeing if its restrictor is in place.

For additional information, check our free boost mod page.

Idle Air Control Stepper Motor Failure (Applies to All Years, All Models)

The idle air control stepper motor can fail and short, potentially damage to the ECU.

During a pre-purchase inspection, you can test for this by turing the air conditioning on full blast and cranking the steering wheel all the way. The RPM should increase if the IAC is doing its job.

For additional information, check our guide to the IAC.

Dented Oil Pans (Applies to All Years, All Models)

Like most cars, our oil pickup is extremely close to the bottom of the oil pan. Dents in the oil pan, however small, can cause oil starvation which can lead to spun bearings and other lack-of-oil related damage.

During a pre-purchase inspection, you can check for this by inspecting the oil pan of the vehicle. It should be smooth and free of malformations and dents.

Rusty Fuel Sending Unit / Fuel Lines (Applies to All Years, All Models)

The fuel sending unit, and the connection between its flex pipe and the main fuel line, are notorious for rusting very badly. If rusted, it is very easy to apply too much force to the flex pipe half when trying to disconnect it from the fuel line, causing irreperable damage to the fuel sending unit.

During a pre-purchase inspection, you can check for this by looking under the car near the fuel tank and checking the fuel line connection for rust, as well as by inspecting under the fuel sender access panel in the trunk.

Boost Leaks (Applies to All Years, Turbo Models)

Our cars have a lot of connections in their turbo intake systems (like most turbocharged vehicles). It is very common for one of these connections to come loose and cause the engine to fall off under boost above a given threshold.

During a test drive, if the vehicle has a boost leak you should feel it stutter or even completely lose power at higher RPM. This can be tested precisely with an intake pressure tester, but it isn't ideal to test for this during a pre-purchase inspection unless you take it to a shop. Fortunately, this is also typically an easy thing to fix.

Vacuum Leaks (Applies to All Years, All Models)

The numerous vacuum lines throughout the vehicle have a tendency to spring leaks, which can cause various vacuum assisted systems to stop functioning properly.

A higher than normal idle is a common symptom of this issue, but there are other potential causes for that as well. This can be tested precisely with a smoke test, but it isn't ideal to test for this during a pre-purchase inspection unless you take it to a shop.

Ignition "Click-No-Start" (Applies to All Years, All Models)

A common issue for the platform is to have the ignition switch fail, which will cause a click sound when you turn the key, but will not engage the starter. It may eventually start after repeatedly cycling the key.

You can test the ignition switch using a multimeter, but this is not ideal during a pre-purchase inspection. As far as no-start conditions go, this is decently easy to resolve. Under no circumstances should you modify your wiring or add a "Click-No-Start" relay until you have ruled out the ignition switch and starter relay which are both easily replacable.

Electronically Controlled Suspension Light (Applies to 1991-1995, Equipped Models)

Phased out starting in 1996, the electronically controlled suspension system can fail in a number of ways which will all result in an ECS light on the dash, unless a previous owner disabled the light. A failed ECS computer can damage the ECU.

This system is more difficult to diagnose, but should not impede a test drive. It can be a negotiating point to bring down the value if it isn't working properly.

Active Exhaust Valve Corrosion (Applies to 1991-1994, Turbo Models)

Phased out starting in 1995, the twin turbo models have an active exhaust which would keep the exhaust note more muted at idle and at cruising RPM.

The valve that controls this system can corrode in place, preventing it from functioning correctly. This isn't a huge deal for most buyers, but can be used as a negotiating point.

Lifter Tick (Applies to 1991-1998, DOHC Models)

Most DOHC motors suffer from "lifter tick", often seen as a consequence of small 1mm ports in the hydraulic lifters used in the engine. The ports were expanded to 3mm for the 1999 model year.

It can be hard to differentiate between lifter tick and valve damage if the tick is severe enough. Lifter tick will typically change in volume once the engine is warm and the oil reaches operating temperature. Valve damage tapping will typically stay the same.

Window Regulator Failure (Applies All Models)

Thanks to Mitsubishi using teflon pullies in the power window regulators, many have started to crank and fail as the plastic ages.

Power window regulators can be replaced fairly easily, but factory ones are becoming harder to find.

Clutch Hydraulic Failure (Applies to Manual Transmission Models)

This is less of a platform specific issue, but the hydaulic clutch cylinders can begin to leak internally, causing difficulty getting the car into gear, especially first and reverse while stopped without rev-matching.

Pumping the clutch will usually resolve this, as opposed to other transmission ailments which will not be helped by building more pressure in the hydraulics.

Automatic Transmission Failure (Applies Automatic Transmission Models)

The automatic transmissions used in the platform are not especially durable, especially subjected to the driving styles of many owners. Many people choose to swap to a 5 speed transmission when their automatic fails.

Thermal Damaged All Wheel Steering Lines (Applies to All Wheel Drive Models, Excluding 1995-1996 Stealth RT/TT)

Most twin turbo models are equipped with an all wheel steering system. Unfortunately due to the steering lines' proximity to the exhaust pipes, as well as exposure to road grime, many of these lines have begun to fail.

Most owners tend to delete the system when it fails, as it can be expensive to repair, but aftermarket line replacement kits do exist.

Active Aerodynamics Failure (Applies to 1991-1996, Mitsubishi Turbo Models Except GTO MR)

Most twin turbo Mitsubishi models are equipped with active aerodynamics systems which will angle the wing and front air dam to improve airflow at high speeds.

Failure in this system is usually caused by damage to the front air dam, which when faulty will prevent the spoiler from operating properly as well.

Power Antenna Failure (Applies to Equipped Models)

The power antennas used in the platform operate with a plastic gear which drives a plastic toothed mast. As with the power window regulators, 25 year old plastic doesn't tend to last very long, so many of these antennas are inoperable.

Many aftermarket antenna options are available.

PTU Failure (Applies to All Models)

The power transistor unit which drives the ignition coils tends to fail more often than it should, which can present with lack of spark on a cylinder bank.

This can be easily diagnosed with a multimeter, but a car with a failed PTU will likely run very poorly, if at all.