ASE A8 Engine Performance practice test
The A8 test is driveability diagnosis: misfires, fuel trim interpretation, OBD-II monitors, and emissions systems. If you can read short- and long-term fuel trim like a story, most of this test opens up — practice exactly that here.
Technician A says clearing diagnostic trouble codes (or disconnecting the battery) resets the OBD-II readiness monitors to incomplete. Technician B says every monitor runs to completion on each engine start, so readiness is restored after one idle period. Who is correct?
How the A8 test works
50 scored questions
+ ~10 unscored research questions
75 minutes
computer-based, at a test center
$62 per test
plus one $34 registration fee per order
Valid 5 years
then a shorter recertification test
ASE does not publish one universal passing percentage; the passing standard is set by test. TorquePrep uses 80% as a conservative practice target, not as an official ASE cut score. The certificate is issued once ASE verifies your required work experience.
What the A8 test covers
The official task list for A8 Engine Performance breaks down into these content areas — the practice bank above draws from all of them:
- General diagnosis — misfire, hard start, surge, hesitation, and power loss
- Ignition system — coils, plugs, and misfire patterns
- Fuel, air induction, and exhaust — pressure/volume testing, injectors, MAF/MAP, vacuum leaks, restricted exhaust
- Emissions systems — EGR, EVAP, PCV, and catalyst efficiency
- Computerized controls — OBD-II monitors, DTC strategy, fuel trim, and oxygen/air-fuel sensors
Frequently asked
- How many questions are on the ASE A8 test?
- The A8 test has 50 scored questions plus about 10 unscored research questions, with a 75-minute time limit.
- How is A8 different from A1?
- A1 is mechanical engine repair — measuring and machining. A8 is driveability and management: sensors, fuel control, ignition, and emissions diagnosis on a running engine.
- What is the single best skill for A8?
- Fuel-trim interpretation. Knowing what high positive trim at idle that normalizes at cruise means (vacuum leak) — and its mirror cases — decides many questions.
Exam length, timing, fees, and content areas checked September 11, 2026 against the official ASE test table and ASE study guides.