RedlineAi
EXAMPLEThis is a scripted walkthrough showing how a diagnosis flows — not a live result. Your real diagnosis is tailored to your exact vehicle.

Watch a real diagnosis

Here’s what a RedlineAi diagnosis actually looks like: you describe the symptom in plain English, answer a couple of guided questions, and get ranked causes, an urgency read, and an honest cost range. Follow along, then try it on your own car →

1. Describe the symptom

No codes or jargon required — though if you have a trouble code, you can paste it in.

Tell me what’s going on with the car — symptoms, sounds, when it happens. The more detail, the better.
My 2015 Honda Civic idles rough and the check engine light is on. It almost stalls at red lights.
Got it. A rough idle that nearly stalls, plus a check-engine light, usually points to a misfire or an air/fuel problem. A couple of quick questions to narrow it down.
Is the check-engine light steady, or flashing?
Steady, not flashing.
Good — steady means no active hard misfire, so we have time to diagnose properly. Have you noticed worse fuel economy or any hesitation when accelerating?
Now that you mention it, mileage has been a bit worse lately.

2. Get a grounded diagnosis

RedlineAi weighs your answers against your exact vehicle and real recall + complaint data, then shows its work — including how confident it is.

Confidence: ModerateGet it checked soonExample · 2015 Honda Civic 1.8L

Most likely: an ignition misfire from worn spark plugs

Your symptoms — a rough idle that nearly stalls, a steady check-engine light, and slightly worse fuel economy — line up most closely with a developing misfire. On this engine at typical mileage, the original spark plugs and coils are the usual starting point.

Other possible causes

  • Worn spark plugs or ignition coilOn a 2015 Civic at typical mileage, original plugs/coils are a leading cause of a rough idle with a steady light and slightly worse economy.
  • Vacuum leakA cracked intake hose or failing gasket lets in unmetered air, upsetting the mixture most noticeably at idle.
  • Dirty throttle bodyCarbon buildup restricts the small airflow used at idle, causing surging and near-stalls at a stop.

What I’d check first

  • Pull the trouble code (a P0300-series misfire code would confirm the direction).RedlineAi’s live OBD reader can do this in seconds.
  • Inspect the spark plugs for wear and the intake hoses for cracks.Cheap checks that resolve most rough idles.

Typical cost to fix: $120–$400 — a tune-up (plugs, and coils if needed) or sealing a vacuum leak.

Safe to drive — for now. A steady light and a mild rough idle are usually okay short-term, but get it checked soon: a misfire tends to worsen and can eventually damage the catalytic converter.

3. Decide with confidence

From here you know what’s likely wrong, how urgent it is, and a fair price range — so you can fix it yourself or walk into a shop already knowing what a reasonable quote looks like. And when a problem genuinely needs hands-on inspection, RedlineAi says so plainly instead of guessing.

Your turn. Describe what your car is doing and get a diagnosis tailored to your exact year, make and model — free to start, no diagnostic fee.

Start a free diagnosis →

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