Top 5 Lexus ES 300 Problems: 3rd Generation (1997 to 2001)

The Lexus ES 300 is a classic luxury sedan, and the ES series has existed for 7 generations since 1989. This post reviews the top 5 Lexus ES 300 problems owners experienced with the 3rd generation, years 1997 to 2001.

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Most Common Issues with the 3rd Gen Lexus ES 300 (1997 to 2002)

1. Idle Air Control (IAC) Valve

Idle Air Control (IAC) Valve on 1997 to 2001 Lexus ES 300
IAC Valve on 1997 to 2001 Lexus ES 300

Symptoms of a Bad IAC Valve

  • Poor, erratic idle
  • Poor fuel economy
  • Hard starting in cold temperature
  • Check engine light

Causes of a Bad IAC Valve

The IAC valve regulates the amount of air entering the engine, an the throttle body regulates the amount of air entering the engine when accelerating.

Carbon can build up on the IAC valve and cause runability issues. If there is carbon on the IAC valve, there is likely carbon build-up in other areas of the air intake system like the throttle body.

How to Fix a Bad IAC Valve

The IAC valve is located underneath the throttle body.

Steps for Fixing a Bad IAC Valve on the 1997 to 2001 Lexus ES 300

  1. Remove the IAC Valve

    Remove the IAC valve and remove any carbon build-up that may be inside.

  2. Clean the IAC Valve with Carbon Cleaner and a Brush

    Remove the carbon build-up with carbon or throttle body cleaner and clean it with a soft bristle brush.

    Tip: Make sure this part is being cleaned over a material or container that can collect the debris since some of the chemicals can be hazardous to the environment.

  3. Test Drive the Car

    Test drive the car and see if cleaning the IAC valve fixed this problem.

  4. If Still Experiencing These Symptoms, Replace the IAC Valve

    If cleaning the IAC valve doesn’t fix this problem, replace it.

2. Oxygen (O2) Sensor Failure

Symptoms of Bad O2 Sensors

  • Check engine light for a specific O2 sensor, multiple O2 sensors, or the catalytic convertor
  • Pollution from the tail pipe
  • Poor fuel economy

Causes of Bad O2 Sensors

The O2 sensors tend to fail on the 3rd gen ES 300. Pollution is caused by a faulty O2 sensor not communicating with the computer.

How to Fix Bad O2 Sensors

There are two banks on the 3rd gen ES 300, and there is one oxygen sensor for each bank.

To fix O2 sensor-related problems, diagnose the issue, and replace the O2 sensor if it’s faulty.

3. Worn Piston Rings

Piston

Symptoms of Worn Piston Rings

  • White or gray smoke from the tail pipe
  • High oil consumption
  • Less engine power or slower acceleration
  • Decreased engine performance

Causes of Worn Piston Rings

The piston rings are located on the piston. They may wear down and provide less of a seal than they are supposed to. Not changing the engine oil consistently at the recommended intervals can increase the chances of this problem occurring. Low engine oil levels or lower engine oil quality make it harder for the engine to lubricate itself, and this can wear out parts like the piston ring.

How to Fix Worn Piston Rings

This job is time consuming and requires the removal of a lot of parts from the engine to access the pistons, but it can be done at home and requires knowledge of the appropriate torque specs and how the piston rings are organized.

4. Ignition Coil Failure

Ignition coils

Symptoms of Ignition Coil Problems on the 1997 to 2001 Lexus ES 300

  • Poor fuel economy
  • Poor acceleration
  • Engine misfires
  • Check engine light

How to Fix Ignition Coil Failure

The ignition coil provides spark to the spark plug for combustion in the engine’s cylinder.

Three ignition coils are located on the front side of the engine and the backside of the engine. The code for the check engine light may indicate there is a problem with one cylinder or multiple cylinders.

If the code reads for one ignition coil, it will be indicated by a singular number at the end of the code, such as P0301 (i.e. cylinder 1).

To diagnose the bad ignition coil

  1. Swap the bad ignition coil with a functional one from a different cylinder
  2. Take a road test and see if the code reads for the same cylinder
  3. If the code reads for the new location of the bad ignition coil, replace the defective ignition coil. If the code still reads for the original cylinder, in this example P0301, there is another issue related to that cylinder, like a broken spark plug.

We recommend replacing all of the ignition coils since they are a wear-part with electrical components.

5. Vacuum Leaks

Symptoms of Vacuum Leak Problems on the 3rd Gen Lexus ES 300

  • Engine runability issues
  • Check engine light for a vacuum leak

Causes of Vacuum Leaks

It’s easy for the vacuum hoses on the air intake to disconnect, like when opening and lifting the air filter housing cover to remove the engine air filter.

How to Fix Vacuum Leaks

Inspect the vacuum lines on the intake system for any disconnected or punctured lines. Plug in any disconnected lines and clear the check engine light.

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3rd Generation Lexus ES300 Model Years

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Top 5 Lexus ES300 Problems - 3rd Generation (1997 to 2001) - 1A Auto
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Learn the top 5 Lexus ES300 problems with the 3rd generation, years 1997 to 2001, as expert mechanics review its most common symptoms and fixes in this video and article
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