1990 Toyota 4Runner Problems

RepairPal has identified the most common problems with the 1990 Toyota 4Runner as reported by actual vehicle owners. We'll tell you what the problem is and what it'll take to fix it.

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19
Known Problems

At higher mileages, (125,000-150,000) the automatic transmission may not shift correctly. This can be caused by the throttle position sensor being out of adjustment or a shift solenoid needing to be replaced. Typically the transmission does not need to be completely overhauled.

The EGR System tends to get restricted or blocked with carbon after 100,000- 125,000 miles which will cause an emissions test failure for NOX. If the EGR system is equipped with an EGR temperature sensor it will trigger a Check Engine Light for improper EGR flow. The repair is to clean out the EGR passages and the EGR Temperature sensor. Our technicians tell this repair is pretty straight forward and takes about 1-1.5 hours. It is also wise to verify the EGR system components i.e. the Transducer, EGR Valve and VSV Solenoid at this time.

At higher mileages (125,00+) the Engine Coolant Temperature Sensor may intermittently stop working, especially when the vehicle is fully warmed up. This can result in illumination of the Check Engine Light and/or an engine stalling problem.

If the car will not start, the most likely problem is worn or corroded solenoid contacts in the starter. Usually, these parts can be replaced without purchasing a new starter.

Front brake rotors can wear causing a pulsation felt in the brake pedal. Our technicians tell us this condition is best corrected by replacement of the front rotors and brake pads.

In some vehicles, the automatic transmissions over heat light may come with sustained highway driving or driving at a sustained speed. Our technicians tell us that flushing the transmission and changing from Dextron lll to Dextron ll can help remedy this problem.

Over the time the exhaust gas recirculation (EGR) system may become plugged with debris, the oxygen sensor may also be getting slow or 'lazy' around this time. When servicing or cleaning  the EGR system, it is a good idea to replace the oxygen sensor because it works in tandem with the EGR system.

If the engine will not crank over, the most common problem is the starter. These will tend to go out at about 100,00-125,000 miles. Sometimes it is only the starter solenoid, but often the complete starter (including solenoid) needs to be replaced.

Brake Fluid can become dirty and may cause problems in the brake system such as an early failure of the Master Cylinder or Wheel Cylinders. The Brake Fluid should be flushed at least every 60,000 miles.

The 3.0 V6 engine is usually prone to leaks in the head gasket after as little as 60,000 miles. When the head gasket is replaced, the knock sensor harness should be replaced as well, as it can be damaged by leaky head gaskets, resulting in a serious decrease in fuel efficiency or in long term engine damage.

The timing chain can develop a rattling noise caused by failing timing chain guides. This is often due to extended mileage intervals between oil changes that allows the oil to become dirty and abrasive which wears away the timing chain guides until they fail. The timing chain and guides should be inspected at each valve adjustment, otherwise serious engine damage may result.

On the 4 Cylinder Engines, the Ignition Coil wire insulation is often rubbed through by the Primary wiring harness which will cause a stalling/no-start condition. The coil wire will need to be replaced and the primary harness will need to be repaired and re-routed.

By 100,000 miles the ignition key tends to wear out and should be replaced or it may not work as well in the door locks or ignition lock cylinder.

At higher mileages (125,000-150,000) the input shaft seal to the power steering gear may leak. It is recommended to replace the steering gear with a quality rebuilt or new unit rather than attempt to re-seal the original unit.

At higher mileages (125,000 -150,000) the power steering pump may begin to leak on the 6 cylinder vehicles and could require replacement.