A Miata pre-purchase inspection is something you can do yourself in about an hour with a flashlight, a magnet, and a floor jack. Do it in daylight, on a dry day, before you fall in love with the car.
Bring: bright flashlight, small magnet, screwdriver or pick, tire gauge, paper towel, and gloves.
Work bottom-up, because the underside decides the car:
- Frame rails: shine along both rails behind the front wheels. Press firmly. Soft or crunchy metal here is the number-one structural killer of NA/NB cars. Holes or Bondo mean walk away.
- Rear subframe mounts: check where the subframe bolts to the body. Rot here is expensive and dangerous.
- Rockers, floors, trunk: lift the carpet and the trunk mat; wet or rusty floors mean blocked drains and hidden corrosion. A magnet finds filler.
Then the mechanicals:
- Cold start: arrive before they warm it up. Listen for VVT rattle (NB2/NC) and knocking; watch for smoke on start and on throttle.
- Timing belt (NA/NB): ask for records; the engine is non-interference, but a failed belt still strands you.
- Fluids: milky oil or coolant means head-gasket trouble; brown crusty coolant means a neglected system.
- Diff and driveline: jack a rear wheel to identify Torsen vs open; feel for driveline clunk.
- Top: check seams, rear window, and latch alignment.
On the test drive, feel for:
- Clutch bite point and any slip under load.
- A gearbox that goes cleanly into every gear, especially cold 2nd.
- Straight-line tracking, even braking, and no wandering.
Decisive rule: grade the body first and let it veto the whole deal. A rust-free car with mechanical wear is a project you finish cheaply; a rusty car with a fresh engine is money poured into a dying shell.