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The Best OBD Scanner for Diagnosing Poor Performance
Written by Joe Ballard
October 7th, 2024
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Experiencing poor performance is not only frustrating but potentially life-threatening. Imagine trying to pull out into oncoming traffic, and when you press the gas pedal, your car suddenly hesitates or dies. This is a terrifying situation, but fortunately, there are things that you can do to avoid it.
In this article, I will identify the typical warning signs of poor performance, the causes of poor performance, and what you can do to identify and fix performance issues before they impact your safety.
Typical Poor Performance Warning Signs
The most common warning sign that your vehicle's engine or emission system is failing is hesitation or slow acceleration. If you notice that you are using more fuel than usual or that your vehicle often stalls or just plain dies for no apparent reason, it's time to take action. These signs indicate that it's not just a matter of maintenance but also your safety. Regular maintenance is critical. However, even if you've been diligent, components can still break or malfunction. Stay vigilant, and don't ignore the warning signs.
What could be causing your vehicle to lose power?
Poor vehicle maintenance causes most issues, but components can also malfunction or fail. If you're experiencing poor performance, one of the first things that will happen is the check engine light (CEL) illuminating. The CEL is good news, as it clearly indicates a problem with the engine or emissions system. However, the bad news is that many possible issues could trigger it. Let’s look at some of the problems that could be causing poor performance.
Maintenance-related:
- The air filter is dirty This usually happens because it has not been changed regularly.
The cost to replace an air filter = $25 - Worn spark plugs – This is usually due to the vehicle's age or mileage, and replacement has been ignored.
Cost to replace the plugs = $10 - $30 each - Clogged fuel filter – This is usually due to bad fuel or other contaminants in the fuel tank.
The cost to replace a fuel filter = $150

Mechanical/Electrical Failure/Malfunction:
- The MAP sensor may be clogged or malfunctioning. This sensor measures air mass flowing into the air cleaner intake. A clogged or bad sensor may send the wrong data to the ECU, resulting in an incorrect calculation of the air-fuel mixture.
- One of the oxygen sensors is bad. This sensor monitors exhaust emissions and sends information to the ECU about the amount of fuel being used. If this sensor is bad, the engine will not receive the correct air-fuel mixture, which may result in a fuel-rich mixture.
- Throttle Position Sensor (TPS) malfunction —The TPS detects the throttle valve opening angle, which is linked to the gas pedal. If the TPS is bad, the engine speed may erratically increase or decrease because the ECU is no longer in the loop.
- Bad fuel injector —This problem may restrict fuel flow, resulting in poor acceleration, hesitation, or stalling.
- Limp mode — If the vehicle ECU detects a problem, it will enter this mode to protect the engine from damage. It will always be accompanied by the CEL turned on, and it will severely impact performance.
- Fuel pump issues — The fuel pump delivers fuel to the engine (fuel injectors or carburetor). If it is bad, the fuel pressure will drop, and you will experience sputtering, stalling, decreased fuel efficiency, or hard starting.
- Clogged exhaust — If the exhaust system becomes clogged or damaged, it could restrict exhaust flow and reduce engine power and acceleration.
- Bad catalytic converter — This type consists of an insulated chamber containing ceramic pellets or a ceramic honeycomb-like structure coated with a thin metal layer, such as Palladium or Platinum. It converts the exhaust gases that pass through the converter to water vapor. It could restrict exhaust flow and reduce engine power and acceleration if it becomes clogged or damaged.
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Key Takeaways
I cannot stress this enough: Regular maintenance and observation of unusual sounds, smells, and fuel consumption will enable you to prevent many issues that could impact your vehicle's performance. Whether the culprit is as simple as a dirty air filter or as complicated as a bad oxygen sensor, regular maintenance that includes an OBD scanner will identify a malfunctioning component before it impacts your performance and safety. In most cases, you will see a CEL, which is the first indication of a problem. Signs such as decreased fuel economy, rough idling, misfires, unusual engine noises or smells, stalling, and black smoke or soot from the exhaust pipe are all possible things to watch for.

As a DIYer, you know that the best course of action to identify the specific problem is to utilize an OBD scanner. Using my 2019 Hyundai Ioniq as an example, I connected the Innova 5610 scanner and the RepairSolutions2 app to perform many of the tests available that will reliably pinpoint specific problems so that you can fix them. Combining the OBD scanner with the Innova RepairSolutions 2 tool will enable you to identify the problem and show you the estimated costs to replace the component.
Conclusion
It is important to remember that being proactive in addressing issues impacting your vehicle performance will ensure you do not get caught in a dangerous situation. Quick action, using an OBD scanner or seeking professional help if you notice any of the warning signs, will enable you to diagnose and fix problems before they leave you stranded with a hefty repair bill or, worse, being involved in a serious accident.
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