Engine misfire at high rpm may result in the deterioration of costly car parts if not promptly diagnosed. Essentially, a misfire indicates the engine’s struggle to ignite the fuel within the cylinders, potentially leading to compromised performance and safety hazards on the road.
So why does an engine misfire at high rpm happen? Mostly, it’s because of ignition system problems. Damaged fuel filters, faulty air filters, imbalance in the air-fuel mixture, etc., could also cause engine misfires.
Timely identification and fixing of misfires are crucial for preserving both vehicle integrity and road safety. Basic car maintenance knowledge is important in diagnosing and fixing not-so-complicated issues.
Engine misfire at high RPM: A Quick Overview of Causes and Solutions
The given chart shows the most common reasons for engine misfire at high rpm and their quick solutions:
| Issues | Symptoms | Solution |
| Ignition System Failure | Rough idling, or lack of power. | Replace worn-out spark plugs and faulty ignition coils. Maintain ignition system regularly. |
| Fuel Delivery Issues | Engine hesitation, stalling, or poor acceleration. | Clean or replace the fuel pump, filter, and injectors as needed. |
| Air Intake System Problems | Abnormal engine noises, such as whistling or hissing. Look for Dirt on the air filter, and cracks or leaks on vacuum hoses. | Replace dirty air filter, repair/replace damaged vacuum hoses, and test mass airflow sensor. Regularly maintain air intake system. |
| Exhaust System Malfunction | Reduced engine power, excessive exhaust noise, or a sulfur-like smell. Measure exhaust back pressure (specification below 1.5 psi at idle). | Inspect and replace the catalytic converter and exhaust manifold if blocked or damaged. |
Causes and Solutions in Detail
Engine misfires at high RPM can stem from various underlying issues. Explore the major reasons below, along with potential solutions.
Ignition System Failure
Ignition system failure results from malfunctioning components like spark plugs, ignition coils, and ignition wires (if available). These parts collaborate to create sparks igniting the fuel-air mixture. Failure leads to issues like misfires, rough idling, and decreased performance.
Diagnosis and Solution:
Spark plugs are typically on the engine’s cylinder head, connected to wires. Ignition coils may be nearby or directly on top, depending on the vehicle.
- Remove and visually inspect spark plugs for wear or damage. Aim for a 0.6-1.0 mm gap. Use a tester for consistent sparking and replace faulty plugs.
- Measure the primary winding resistance of ignition coils (0.4-2.0 ohms). Swap suspected faulty coils. Replace coils with abnormal resistance readings.
Fuel Delivery Issues
Providing the engine with the needed amount of fuel at the right time is the job of the fuel delivery system. But issues may occur due to faulty or clogged fuel filters or pump.
Fuel injector issue or faulty sensors can also disrupt fuel flow. Stalling, poor acceleration, and reduced fuel efficiency are some common symptoms.
Diagnosis and Solution:
It is spread throughout the car. But most components can be seen underneath the vehicle.
- And visually inspect for debris or sediment. Blow air through it or gently tap to dislodge any blockages. If significant clogs are found, replace the filter to restore proper fuel flow.
- To check for fuel line leaks, visually inspect for damage and feel for wetness. Repair or replace any damaged lines immediately to prevent hazards. Ensure all connections are secure and monitor for leaks while the engine is running.
- Inspect fuel injectors for leaks, clogs, or malfunctions. Use a stethoscope or injector tester to ensure proper operation and even fuel delivery. Clean or replace faulty injectors as needed.
- Scan for error codes with a diagnostic scanner to identify fuel system issues. Address any codes related to sensors, injectors, or the fuel pump accordingly.
You can learn how to use OBD-II scanner from the video given below:
Air Intake System Problem
The job of the air intake system is to provide the engine with clean and purified air. So if an intake system is faulty, you may hear unusual hissing or whistling engine sound, which is a common symptom.
Diagnosis and Solution:
The air intake system is usually connected to the intake manifold or an area where it can blow out engine air outside.
- Remove the air filter and visually inspect it for debris or clogs. Replace if it is too dirty or too clogged to clean.
- The throttle body, vacuum hoses, and intake manifold may have cracks or blockages. Use a vacuum gauge to check for leaks in the vacuum hoses. Clean or replace the parts if necessary.
Exhaust System Malfunction
The job of an Exhaust system is to purify the exhaust gas and lead it away from the vehicle. Exhaust noise is kept under control with its help. So if you hear too much exhaust noise or less engine power, something may need to be fixed with your exhaust system.
Diagnosis and Solution:
The exhaust system is mostly located underneath a car, facing the ground. It consists of a catalytic converter, exhaust manifold, and other sections.
- Inspect exhaust for damage like dents, leaks, or collapses. Repair or replace damaged components as needed, including welding dents, patching leaks, or replacing collapsed sections.
- Use a pressure gauge to measure exhaust pressure, and perform a back pressure test. Clear obstruction by removing debris, unclogging pipes, or replacing faulty components like catalytic converters. Retest for proper exhaust flow.
- Inspect the catalytic converter for damage or clogging. Replace if necessary.
- Use a diagnostic scanner to check for error codes related to the exhaust system. Address underlying issues identified by automotive trouble codes, like replacing faulty oxygen sensors or repairing the catalytic converter.
If your car experiences engine misfire at high RPM, you might find our article on ‘Car Engine Misfire at Low RPM and Can a Bad Alternator Cause a Misfire?’ beneficial, covering everything you’ll ever need. What Causes a Car Engine to Misfire at Low RPM? Offers a comprehensive examination of the common factors contributing to engine misfires at lower speeds. Meanwhile, our piece on Can a Bad Alternator Cause a Misfire? delves into everything you need to know about this aspect.
Frequently Asked Question
Apart from the mentioned causes, many other reasons can make the engine misfire while at full rpm. Being alert about some basic car maintenance information should help detect these issues as well.
Does compression loss cause the engine to misfire at high rpm?
Yes, it can. When the compression is insufficient, the combustion of the air-fuel mixture remains incomplete.
Is engine failure a potential risk of engine misfire at high rpm?
It certainly is. Engine misfires might overheat engine components and damage parts like valves, pistons, and cylinder walls, eventually causing engine failure.
Can ignition timing affect engine misfire at high rpm?
Yes, the wrong ignition timing can cause the engine to misfire at full throttle. This happens as wrong timing causes irregular air-fuel mixture combustion.
We can say that Proper diagnosis and regular checkups are essential for preventing engine misfires at high rpm.
While you can try fixing some issues on your own, complex issues require the expertise of a professional for better results. Rest assured, following manufacturer-recommended care guidelines and proper diagnostic steps can help your vehicle last a long time.