Two U.S. federal sources, both of which publish machine-readable data:
Fuel economy and configuration data — the Department of Energy / EPA fuel economy certification dataset. One row per certified configuration, including engine, transmission, drive type, city and highway mpg, annual fuel cost, tailpipe CO₂, and the EPA's own greenhouse gas score.
Recalls, complaints and crash ratings — NHTSA. Recall campaigns with the official consequence and remedy text; owner complaint filings; New Car Assessment Program star ratings per tested configuration.
Diagnostic codes — generic OBD-II codes only, as defined by SAE J2012 / ISO 15031-6.
Manufacturer-specific diagnostic codes. Their definitions differ by brand and there is no public authority to verify them against. A P1xxx code means something different on a Honda than on a Ford, and guessing is how people replace the wrong part.
Unadjusted EPA test values. Real, published, and not what appears on a window sticker. Mixing them with adjusted values is a quiet way to make every car look more efficient than it is.
Manual files. We link to the manufacturer's own owner site. We do not host or mirror PDFs — the copyright stays with the manufacturer, and a mirror is exactly what gets a site like this taken down.
Torque and fluid specifications we have not verified. This is the biggest gap on the site and we are not going to paper over it.
A wrong torque value destroys an engine. A wrong fluid capacity destroys a transmission. Neither error is visible until it is expensive.
So: if we cannot point at the official document, the field stays empty and labels itself as missing. Some tables on this site look sparse. That is deliberate.
Every figure on a model-year page names its source and its retrieval date. The fuel economy dataset is a public CSV, and each configuration row here maps back to a row in that file by EPA vehicle ID and engine ID. If a number here disagrees with the source file, we got it wrong and we want to hear about it.
More brands, one at a time and finished completely before the next one starts. Fluid capacities and torque values, model by model, but only after we can verify them against official service documentation.