ASE A8
Engine Performance (A8)
The ASE A8 Engine Performance test covers driveability and emissions diagnosis: engine testing, ignition, fuel, air induction and exhaust, emissions controls, and computerized engine controls with OBD II. It is taken by technicians who diagnose drivability concerns and counts toward ASE Master Automobile Technician status.
- Questions you sit
- 60
- Scored
- 50
- Time allowed
- 75 min
- GearheadPass questions
- 151
From ASE's 2026 study guide. The test includes 10 unscored research questions you can't tell apart from the scored ones.
Content areas and weights
| Content area | Questions on the test | Share | Free practice |
|---|---|---|---|
| General Diagnosis | 12 | 24% | 5 questions → |
| Ignition | 8 | 16% | 5 questions → |
| Fuel, Air Induction & Exhaust | 9 | 18% | 5 questions → |
| Emissions Control | 8 | 16% | 5 questions → |
| Computerized Engine Controls | 13 | 26% | 5 questions → |
Study each area
A8 · 12 questions on the test
General Diagnosis
Broad engine performance diagnosis: base engine mechanical tests, vacuum, compression and leak-down, cam timing, cooling, oil-related issues, and battery, starting and charging effects.
A8 · 8 questions on the test
Ignition
Diagnosing ignition-related no-start, misfire, knock, power loss and emissions problems, including primary and secondary circuits, coils, sensors, and ignition and engine control modules.
A8 · 9 questions on the test
Fuel, Air Induction & Exhaust
Diagnosing fuel delivery, air induction and exhaust problems on port and direct injection engines: fuel trim, pumps and pressure, injectors, throttle bodies, vacuum leaks and turbochargers.
A8 · 8 questions on the test
Emissions Control
Diagnosing emission control systems: PCV, EGR, secondary air injection and catalytic converters, and evaporative (EVAP) controls, using scan data and DTCs.
A8 · 13 questions on the test
Computerized Engine Controls
Diagnosing engine computer systems: DTCs, freeze frame and OBD II monitors, faults with or without codes, sensors and actuators, power and ground circuits, PCM programming and networks.
Take a full-length A8 mock in the app
60 questions in 75 minutes, weighted like the real test, scored by content area, with English or Spanish on every question.
