Fuel Trim Analyzer
Interpret STFT and LTFT patterns to separate vacuum leaks, MAF issues, fuel pressure problems and rich conditions.
Interactive preview
Rule-based guidance, not a final repair diagnosis.
Suggested direction
Positive trims on both short and long term suggest unmetered air, low fuel pressure, dirty MAF data, or an exhaust leak before the upstream O2 sensor. Start with an intake smoke test and MAF review.
This tool helps prioritize checks. Safety-critical symptoms, fuel leaks, brake faults and flashing check engine lights should be inspected by a qualified technician.
How to use this tool safely
- Save the original code and freeze-frame data before clearing anything.
- Use the result as an inspection order, not as proof that a part is bad.
- Confirm power, ground, signal, vacuum, pressure or mechanical condition before replacing expensive parts.
When this tool is useful
Fuel Trim Analyzer is meant to read scan data together with symptoms, vehicle behavior and a sensible first-check order. Treat the result as a triage guide, not a final diagnosis. When several codes appear together, confirm battery voltage, connectors, fuses, leaks, fuel data and air measurement values before replacing parts.
How to read the result
- Start with safety: brake warnings, oil pressure, overheating or heavy smoke need immediate attention.
- Do not jump to one part; the same symptom can come from a sensor, wiring, an air leak or fuel delivery.
- After repair, clearing the code is not enough; verify with a short drive cycle and live data.