Car Jerks and Loses Power at Highway Speed - Top Causes, Fixes & What to Do

Certified Professional Automotive Mechanic – Owner and Editor of VehicleRuns

Last Updated: August 29, 2026

Safety note: Troubleshooting guidance can help you narrow down likely causes, but it cannot replace an in-person inspection. If the vehicle feels unsafe, warning lights are flashing, you smell fuel, see smoke, notice overheating, or have problems with braking, steering, or control, stop driving when it is safe to do so and have the vehicle inspected.

If your car jerks and loses power at highway speed, the problem usually is not random. That combination often means the engine or drivetrain cannot deliver smooth power when demand rises, especially under steady speed, moderate acceleration, hills, or passing.

In real-world diagnosis, the key clues are when it happens, whether the check engine light comes on, whether engine RPM changes with the jerking, and whether the car feels like it is choking, misfiring, or slipping. A problem that only shows up at 60 to 75 mph points in a different direction than one that happens at any speed.

Common causes range from ignition misfires and fuel delivery problems to airflow sensor faults, a restricted catalytic converter, or a transmission issue. Some are fixable without major repair, but others can damage the engine or leave you unable to maintain speed safely.

Start with the pattern of the power loss. A flashing check engine light, an RPM flare, or a choked feeling at higher speed each points to a different first check.

What you notice	Most likely cause	What to check first	Urgency
Check engine light flashes during jerking	Engine misfire	Scan for misfire codes and inspect coils and spark plugs	Stop driving
Pulls weakly above 55 mph or uphill	Low fuel pressure	Test fuel pressure under load and check fuel filter history	Can worsen
Feels choked and will not rev freely	Restricted catalytic converter	Check exhaust backpressure or compare inlet and outlet cat temperatures	Can worsen
Jerking is worse in damp or rainy weather	Ignition coil or boot arcing	Inspect coils and boots for cracks, tracking, or moisture intrusion	Diagnose soon
RPM jumps but speed does not increase normally	Transmission or torque converter problem	Check transmission fluid condition and scan transmission-related codes	Can worsen

Best first move: If the problem happens consistently at highway speed, scan for codes first, then separate engine-side power loss from transmission slip by watching RPM behavior during the event.

Safety note: Stop driving if the check engine light is flashing, the car cannot hold speed in traffic, or the jerking is severe enough to create a stall or merging hazard.

Table of Contents

Most Common Causes of a Car Jerking and Losing Power at Highway Speed

The three causes below are the most common starting points for this symptom pattern. A fuller list of possible causes and confirmation checks appears later in the article.

Engine Misfire or Weak Ignition: A weak coil, worn spark plug, or ignition problem often shows up most clearly at highway speed because cylinder demand is higher under load.
Low Fuel Pressure or Restricted Fuel Delivery: If the engine cannot get enough fuel at sustained speed or while climbing, it may surge, jerk, and fall flat even if it idles normally.
Restricted Catalytic Converter: A clogged converter can make the engine feel strangled at higher RPM, often causing loss of power that gets worse the longer you drive.

What a Car Jerking and Losing Power at Highway Speed Usually Means

A car that jerks and loses power at highway speed usually has a problem that shows up under load rather than at idle. At lower speed, the engine may seem mostly normal because it does not need as much fuel, spark energy, airflow, or exhaust flow. Once speed rises, the weak part starts showing itself.

One of the most useful splits is whether the problem feels like the engine is stumbling or whether the transmission feels like it is slipping. If the engine bucks, hesitates, or sounds uneven, look first at misfire, fuel delivery, airflow, or exhaust restriction. If RPM suddenly rises without matching road speed, transmission or torque converter problems move higher on the list.

Another key clue is whether the symptom is tied to hills, passing, hot soak, or long freeway drives. A fuel pump that is getting weak may struggle more when hot or under heavy demand. A restricted catalytic converter may feel acceptable at first, then become much worse after sustained driving. Ignition problems often get worse in damp weather or during moderate throttle.

Warning lights matter here. A flashing check engine light strongly suggests an active misfire, which can overheat and damage the catalytic converter. A steady check engine light still matters, but the immediate risk is usually lower unless the car is losing speed rapidly or running very rough.

Possible Causes of a Car Jerking and Losing Power at Highway Speed

Engine Misfire or Weak Ignition

At highway speed, cylinder pressure rises and the ignition system has to work harder to fire the mixture cleanly. A worn spark plug, weak ignition coil, or failing plug boot can misfire under load even if the engine idles fairly well, causing bucking, surging, and sudden power loss.

Symptoms to Watch For

Flashing or steady check engine light
Roughness during passing or climbing hills
Jerking that gets worse in damp weather
Raw fuel smell from the exhaust
Noticeable stumble without a big RPM flare

High Severity

An active misfire can quickly overheat the catalytic converter, reduce control in traffic, and lead to a breakdown if ignored.

How to Confirm: Scan for trouble codes first, especially misfire codes such as P0300 through P030x.

Typical fix: Replace the failed spark plug, ignition coil, plug boot, or related ignition components and clear the codes.

Low Fuel Pressure or Restricted Fuel Delivery

An engine needs much more fuel volume at highway speed and under load than it does at idle. A weak fuel pump, clogged filter, restricted pickup, or failing pressure regulator can allow normal low-speed driving but starve the engine at freeway speed, leading to jerking and loss of power.

Symptoms to Watch For

Feels worse on hills or during passing
May improve briefly after lifting off the throttle
Hard starting after sitting in some cases
Whining fuel pump noise from the tank area
Lean codes or random hesitation

Moderate to High Severity

The car may become unable to maintain speed or may stall under demand, which is risky on the highway and can leave you stranded.

How to Confirm: Measure fuel pressure and, when possible, fuel pressure under load during a road test.

How to Diagnose Low Fuel Pressure or Restricted Fuel Delivery

Typical fix: Replace the weak fuel pump, clogged filter, failed regulator, or restricted fuel delivery component.

Restricted Catalytic Converter

A clogged converter creates exhaust backpressure, so the engine cannot breathe out properly at higher RPM. That makes the car feel flat, choked, and unwilling to accelerate, especially after sustained highway driving or when climbing grades.

Symptoms to Watch For

Poor acceleration at higher RPM
Engine feels better at low speed than on the freeway
Excess heat under the vehicle
Sulfur or hot exhaust smell in some cases
Possible rattling if the substrate is breaking up

Moderate to High Severity

A restricted converter can overheat, worsen quickly, and create unsafe power loss in traffic, especially when merging or climbing.

How to Confirm: Check exhaust backpressure with the proper gauge or compare converter inlet and outlet temperatures with an infrared thermometer as part of a broader test plan.

How to Diagnose Catalytic Converter Problems

Typical fix: Replace the restricted catalytic converter and correct the underlying cause if misfire or rich running damaged it.

Dirty or Faulty Mass Air Flow Sensor

The engine computer relies on the mass air flow sensor to calculate fuel delivery. If the sensor under-reports airflow or becomes erratic, the air-fuel mixture can go lean or unstable at highway speed, causing hesitation, surging, and weak acceleration.

Symptoms to Watch For

Hesitation without a severe misfire feel
Reduced power after recent air filter or intake work
Check engine light with airflow or fuel-trim codes
Improves temporarily after restarting in some vehicles
Idle may be slightly rough but not always

Moderate Severity

This usually will not cause immediate mechanical damage, but it can make the vehicle unpredictable at speed and may contribute to converter damage over time.

How to Confirm: Scan for MAF-related or fuel-trim codes and review live airflow data at idle and during a loaded road test.

How to Diagnose a Dirty or Faulty Mass Air Flow Sensor

Typical fix: Clean the sensor if contamination is the issue or replace the faulty mass air flow sensor and repair any intake leaks.

Restricted Engine Airflow or Dirty Air Filter

If the engine cannot draw enough clean air, power drops most noticeably at higher speeds and heavier throttle. A badly clogged air filter, collapsed intake duct, or obstruction in the intake path can make the engine feel flat and occasionally surge as airflow changes.

Symptoms to Watch For

Power loss is worse at wide throttle
No strong misfire feel
Recent driving in dusty conditions
Whistling or intake noise from the air box area
Dirty or overdue air filter

Low Severity

This is usually less urgent than a misfire or fuel problem, but it can still make highway driving frustrating and can hide other issues if ignored.

How to Confirm: Inspect the air filter, intake snorkel, ducting, and air box for blockage, collapse, or rodent debris.

Typical fix: Replace the dirty air filter and repair or replace the restricted intake duct or air box component.

Torque Converter or Torque Converter Clutch Problem

Some highway-speed jerking is not engine power loss at all. A failing torque converter or unstable converter clutch can shudder, surge, or feel like repeated small slips at steady freeway speed, especially when cruising lightly in the lockup range.

Symptoms to Watch For

RPM fluctuates during steady cruise
Jerking is strongest around one highway speed
May feel better with overdrive off
Transmission fluid may look dark or smell burnt
No obvious misfire sound from the engine

Moderate to High Severity

Converter or transmission problems often worsen with continued driving and can turn a shudder into a more expensive internal failure.

How to Confirm: Watch engine RPM closely during the event.

How to Diagnose Torque Converter Problems

Typical fix: Replace the failed torque converter or repair the related transmission control or internal transmission fault.

How to Diagnose the Problem

Confirm the exact pattern by noting speed, throttle position, road grade, and whether the problem happens only after the car is fully warm.
Watch the dash when the jerking occurs. A flashing check engine light moves misfire to the top of the list.
Pay attention to engine RPM during the event. If RPM flares without matching speed, think transmission or torque converter before engine power loss.
Scan for stored and pending trouble codes even if the light is off. Misfire, lean, airflow, catalyst-efficiency, and transmission codes all matter here.
Inspect basic maintenance items first, including spark plugs, ignition coils, air filter condition, intake ducting, and obvious loose connectors.
If the symptom shows up under load, test fuel pressure and, if possible, pressure behavior during a road test or simulated load.
Check for signs of exhaust restriction if the engine feels choked at higher RPM, especially if power falls off more the longer you drive.
Review live data such as fuel trims, mass air flow readings, misfire counters, and converter clutch command where applicable.
If recent fuel quality is questionable, consider contaminated fuel before replacing major parts.
If the problem is still unclear, have the vehicle diagnosed under actual highway-load conditions rather than only at idle in the shop.

Can You Keep Driving When a Car Jerks and Loses Power at Highway Speed?

Important: The guidance below is general and cannot confirm that your specific vehicle is safe to drive. If a symptom affects braking, steering, handling, fuel, overheating, smoke, visibility, or vehicle control, treat it as potentially serious and have the vehicle inspected before continued driving when appropriate. For more context, see our Automotive Safety Disclaimer.

Whether you can keep driving depends on how severe the jerking is and what is causing it. Some cases allow a cautious short trip. Others should be treated as a stop-driving problem because highway power loss can become a safety issue fast.

Okay to Keep Driving for Now

Only if the jerking is mild, there is no flashing check engine light, the car still holds speed normally, and the symptom is infrequent enough that you can avoid heavy throttle and highway traffic until diagnosis.

Maybe Okay for a Very Short Distance

A very short trip may be reasonable if the car runs mostly normally but hesitates during passing, hills, or sustained freeway speed. Keep the trip local, avoid busy highways, and address it soon because fuel, ignition, and converter problems often worsen.

Not Safe to Keep Driving

Do not keep driving if the check engine light is flashing, the car is bucking hard, speed drops unexpectedly, RPM surges wildly, or you cannot maintain safe traffic flow. This is especially true if the vehicle may stall or the catalytic converter could be overheating.

How to Fix It

The right fix depends on whether the jerking comes from combustion, fuel delivery, airflow, exhaust restriction, or the transmission. The best approach is to confirm the failure pattern first, then repair the actual cause instead of replacing parts at random.

DIY-friendly Checks

Start with code scanning, air filter inspection, intake duct checks, basic connector inspection, and a visual look at ignition coils and spark plug condition if accessible.

Common Shop Fixes

Typical shop repairs include spark plug and coil replacement, fuel pressure diagnosis and pump service, MAF sensor replacement, and catalytic converter replacement after confirming restriction.

Higher-skill Repairs

Deeper repairs can include loaded fuel-system testing, transmission and torque converter diagnosis, exhaust backpressure testing, and advanced live-data analysis during a road test.

Related Repair Guides

Typical Repair Costs

Repair cost depends on the vehicle, local labor rates, and the exact root cause. The ranges below are typical U.S. parts-and-labor estimates, not exact quotes for every make and model.

Spark Plug and Ignition Coil Replacement

Typical cost: $180 to $700

This range fits common four- to six-cylinder repairs, with cost rising if multiple coils are replaced or access is difficult.

Fuel Pressure Diagnosis and Fuel Pump Replacement

Typical cost: $350 to $1,200+

The cost depends heavily on whether the issue is a simple external component or an in-tank pump module.

Mass Air Flow Sensor Cleaning or Replacement

Typical cost: $80 to $450

Cleaning is inexpensive, but replacement costs more when the sensor housing or intake assembly is part of the unit.

Air Filter and Intake Restriction Service

Typical cost: $30 to $250

This usually stays on the low end unless damaged intake ducting or air box parts also need replacement.

Catalytic Converter Replacement

Typical cost: $700 to $2,500+

Converter cost varies widely by vehicle and emissions setup, and underlying misfire damage may add diagnosis time.

Torque Converter or Transmission Repair

Typical cost: $900 to $4,500+

Costs stay lower for some converter-related repairs but rise sharply if internal transmission work is required.

What Affects Cost?

Engine layout and how hard components are to access
Whether the problem is confirmed early or after repeated misdiagnosis
OEM versus aftermarket part choice
Whether one failed part damaged another, such as a misfire damaging the converter
Local labor rates and transmission or exhaust specialty shop pricing

Cost Takeaway

If the car mainly shows a stumble with a check engine light, costs often land in the lower to mid range because ignition and airflow faults are common. If it feels starved for fuel under load, expect a mid-range repair. If the engine feels choked by exhaust restriction or the transmission is slipping or shuddering, repair costs can climb quickly.

Symptoms That Can Look Similar

Parts and Tools

FAQ

Can Bad Gas Make a Car Jerk and Lose Power at Highway Speed?

Yes. Contaminated or low-quality fuel can cause hesitation, weak acceleration, and misfire-like jerking, especially under load. If the symptom started soon after filling up, fuel quality belongs high on the list.

Why Does My Car Only Jerk at 60 to 70 Mph?

That usually means the problem shows up under a specific load or operating range. Ignition weakness, low fuel pressure, converter clutch shudder, and exhaust restriction often become obvious only at steady highway speed.

Is a Flashing Check Engine Light Serious when the Car Is Jerking?

Yes. A flashing check engine light usually means an active misfire. Continued driving can damage the catalytic converter and may cause the engine to run badly enough to become unsafe.

Can a Clogged Catalytic Converter Cause Jerking and Power Loss Without Much Noise?

Yes. A restricted converter often causes a choked, flat feeling rather than a loud sound. The car may idle fairly well but struggle badly at higher RPM or on hills.

How Do I Tell Engine Power Loss From Transmission Slipping?

Watch engine RPM during the event. If the engine bucks and sounds uneven, think engine-side issues first. If RPM rises or hunts without matching speed increase, transmission or torque converter problems become more likely.

Final Thoughts

When a car jerks and loses power at highway speed, the most useful first step is to match the pattern before replacing anything. A flashing check engine light, a weak-under-load feel, a choked high-RPM feel, and an RPM flare each point to different systems.

Start with code scanning and the most common causes: ignition misfire, fuel delivery trouble, airflow faults, and exhaust restriction. If RPM behavior suggests slip instead of stumble, shift your focus to the transmission or torque converter. The sooner you separate those paths, the faster and cheaper the fix usually is.