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.
29 recurring problems · 349 people · 5 forums we read
Raised more than once
Most people first.
- 3Why does AFR drop and fuel trim go negative when coming to idle?When returning to idle after the engine is fully warmed up, the air-fuel ratio drops and short-term fuel trims dip temporarily for about 10 seconds, accompanied by a slightly different exhaust note. Cleaning the MAF sensor, air filter, and throttle body does not fix the issue, leaving drivers dealing with fluctuating RPMs in traffic.
- 3Why does my car die right after a jump start?When a jump-started car engine dies immediately upon idling or letting off the gas, it fails to stay running on its own power. This leaves drivers unable to drive the vehicle anywhere since the engine bogs down and cuts out the moment assistance is removed.
- 2Why does my car misfire when it rains?Moisture gets into components like the ignition system, distributor cap, battery, and coil during wet weather, causing the car to struggle to start or misfire badly when accelerated. Drivers are left stranded with a vehicle that won't turn over or hesitates heavily until everything dries out.
- 2Why is my city gas mileage so terribly low?Many vehicles suffer from severely reduced city fuel economy—dropping to around 10 to 18 miles per gallon—even without warning lights or issues like dragging brakes. Standard maintenance tasks such as changing spark plugs, replacing air filters, cleaning the MAF sensor, or getting new tires often fail to fix the problem. This leaves drivers dealing with sluggish acceleration and short full-tank ranges that make city driving frustratingly expensive.
- 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.
- 2Does high RPM driving actually damage your engine?High RPM driving can feel strained and noisy, making it easy to worry about damage to pistons and seals. However, maintaining proper vehicle care means that higher revs and occasional accidental high-RPM driving—like leaving a car in low gear—won't inherently ruin a properly functioning engine.
- 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.
- 2Engine RPM drops right after starting unless I give it gasThe engine's RPM falls below 500 immediately upon starting, forcing you to apply the throttle to keep the car running. Once the engine warms up and becomes heat-soaked, it loses power, backfires, and suffers from single-digit gas mileage. This condition triggers lean and rich error codes, often prompting owners to replace the O2 sensor.
- 2Why won't my car go past 4k RPM when flooring it?The car automatically shifts at 4,000 RPM instead of reaching the higher rev limiter, even when flooring the gas pedal. This prevents the engine from revving fully and makes the vehicle exceptionally slow to get up to speed. The restriction is often caused by a broken speed sensor, which may also trigger a lightning bolt and traction control warning light on the dashboard.
Comes up alongside
Topics that keep appearing on the same problems — not topics with similar names.