Loss of Power or Performance
Engine feels sluggish, weak, or lacks normal acceleration.
Check These First
Before diving into diagnosis, quickly verify these:
- 1Note if problem occurs on flat roads, hills, or loaded driving
- 2Check if check engine light is illuminated
What exactly is it doing?
Pick the description that fits best.
Car Hesitates or Jerks When Accelerating
Fix SoonHesitation or jerking during acceleration means the engine or drivetrain is not delivering smooth power under load. Common causes include misfires, worn spark plugs, weak ignition coils, fuel delivery problems, dirty fuel injectors, mass airflow sensor faults, vacuum leaks, torque converter shudder, or transmission slipping.
See causes →Car Stalling or Dying While Driving
Fix SoonA car that stalls or dies while driving is losing the ability to keep the engine running. Common causes include a failing fuel pump, ignition failure, crankshaft/camshaft sensor faults, alternator or charging issues, dirty throttle body, mass airflow sensor problems, severe vacuum leaks, or transmission/torque converter problems at stops.
See causes →Engine Stalling While Driving
Fix SoonEngine unexpectedly shuts off while car is in motion.
See causes →Rough Idle or Hesitation
MonitorEngine stumbles or pauses during acceleration from stop.
See causes →Related Symptoms in Engine
Other problems to check if this isn't your issue.
Burning Smell Diagnosis
Fix SoonA burning smell from your vehicle has several distinct types. Burning rubber can mean a slipping belt, dragging brakes, or a hose touching the exhaust. Hot oil smell means oil is dripping onto a hot surface. Burning plastic or electrical smell means wiring or insulation is overheating. A sweet or caramel smell usually points to coolant. Identifying the smell type and when it occurs helps narrow the problem before any parts are checked.
Car Won't Start
Fix SoonYour car won't start, meaning the engine doesn't turn over when you turn the key or press the ignition button. This is usually caused by a dead or weak battery, a faulty starter motor, or a bad alternator. Check your battery connections first, and if that doesn't help, you'll likely need professional diagnosis to identify whether it's an electrical issue or a fuel/ignition problem.
Check Engine Light On
Fix SoonA steady check engine light means the vehicle computer stored a fault related to the engine, emissions, fuel, ignition, air intake, or sometimes transmission controls. The only accurate first step is reading the code, then diagnosing the system the code points to.
Engine Noise Diagnosis
Fix SoonEngine noises at idle, startup, or under load need to be separated by location, oil pressure, RPM change, and whether the noise is ticking, knocking, rattling, or hissing.
Engine Won't Start
Fix SoonEngine fails to crank or turn over when you turn the key.