What people keep running into with engine performance
Complaints tagged engine performance, each raised by more than one person. One-off posts are not included.
15 recurring problems · 134 people · 4 forums we read
Raised more than once
Most people first.
- 32Why does my car make a loud rattle when starting the engine?An engine startup rattle indicates a mechanical noise occurring immediately upon ignition. This issue stops the engine from idling smoothly and can cause severe shaking throughout the vehicle cabin.
- 18Why does my car run terribly and stutter after a long drive?Extended driving triggers severe engine sluggishness, unusual valve train noises, and random cylinder misfire codes. These sudden performance drops cause RPM stuttering and electrical warnings that leave drivers stranded and unable to reach a diagnostic scanner.
- 15Why are my oxygen sensor readings going crazy during a misfire?Conflicting lambda readings ranging from very rich to ultra-lean make it nearly impossible to pinpoint the root cause of an engine misfire using standard data alone. This erratic sensor behavior prevents car owners from identifying whether the issue stems from failing injectors, fuel delivery problems, or sensor faults.
- 13Intermittent car hesitation with no trouble codesElectrical or charging system anomalies—such as a weak alternator or hidden voltage drops—can disrupt powertrain sensors without setting a diagnostic trouble code. This leaves owners replacing mechanical components in circles while the underlying power supply fault continues to trigger random engine or transmission hesitation under load.
- 12Why does my car stall when I come to a stop?Vehicles sometimes shut off or shake and drop RPMs when coming to a stop sign, red light, or while reversing early in a drive. This happens even with accessories like the AC and radio turned off, leaving drivers uncertain about mechanical issues while a persistent P0328 code returns.
- 10Why does my car lose power when I step on the gas?The engine accelerates fine under light input but bogs down, bounces revs, or stops gaining speed entirely when the pedal is floored. This prevents the vehicle from speeding up past a certain threshold or responding when full power is demanded to pass or merge.
- 9Why does my car engine cut out after driving for a while?An engine can die after thirty to forty minutes of driving, behaving as though it is out of fuel despite a full tank, and then refuse to restart for an hour or two until it cools down. This sudden loss of power and shutdown leaves drivers stranded and unable to rely on their vehicle for daily use.
- 7Why does a car shake when idling after sitting for years?Vehicles left sitting unused for long periods often develop heavy vibrations in gear and reverse upon startup, leaving owners stranded without knowing where to begin troubleshooting. This makes it difficult to restore an older vehicle to a drivable state without wasting money on random parts.
- 5Why does my car lurch and shake when I accelerate at low RPMs?Heavy acceleration at low RPMs causes the vehicle to violently shake, lurch, and make clunking noises, while smaller inputs can trigger rough, punchy downshifts. This makes driving unresponsive and jarring, preventing smooth acceleration from low speeds.
- 4Why does my car jerk and whine when accelerating around a turn?Car jerking and whining exclusively during turns while pressing the gas pedal usually points to a drivetrain or differential issue, since the problem disappears when driving in a straight line. This sudden kicking sensation makes driving unpredictable and prevents normal, smooth acceleration from a stop or around corners.
- 3Why is my car revving so high on a cold start?An engine running at excessively high RPMs during a cold start is typically caused by a vacuum leak, a faulty idle air control valve, or a stuck throttle body. This sudden surge prevents the vehicle from idling down normally and often triggers related fault codes like a P0420 catalytic converter error.
- 2Catalytic converter clogged without check engine lightA catalytic converter can fail and severely restrict exhaust flow without triggering a malfunction indicator lamp, leading to gradual power loss and an inability to climb hills. Because diagnostic trouble codes do not always appear, drivers struggle to confirm whether the restriction is actually inside the exhaust system.
- 2Why does my car go into limp mode after warming up?Oil on the ECM plugs can cause a vehicle to repeatedly drop into limp mode a few minutes after warming up while throwing code P1125. This restricts speed to around four miles per hour, leaving drivers uncertain if it is safe to drive to a garage without risking engine damage.
- 2Turbo charge hose collapsing on accelerationThe turbo charge pipe collapses inward almost fully under high throttle, which restricts airflow and causes a sudden loss of boost. This issue triggers an amber drivetrain warning and prevents the engine from maintaining power during hard acceleration.
- 2Why is my new turbocharger screaming after a few hundred miles?A newly installed aftermarket turbocharger can fail within a few hundred miles, marked by a loud screaming noise that signals total internal failure. This premature breakdown leaves owners dealing with cooked components and trying to determine if the issue stems from an off-center compressor nut or underlying installation conditions.
Comes up alongside
Topics that keep appearing on the same problems — not topics with similar names.