Why does my Toyota Supra sputter when cold or not start after storage?

Short answer: On the 7M-GE Supra, a cold-only sputter often comes from the cold-start system: the cold start injector, the thermo time switch that controls it, or the coolant temperature sensor the computer reads. These older computers don't check whether sensor readings make sense, so a sensor can be wrong without setting a code. One owner's workaround was turning the key on for two seconds, off, then starting. A Supra that won't start after months of storage may simply have stale gas.

Symptom: The car spits and sputters until it warms up, then runs fine. Or after sitting all winter, it ran on a short test drive, then the next day cranked but wouldn't start.

What to check first

1. Test the cold start injector and thermo time switch with the service manual procedure.
2. Check the coolant temperature sensor that feeds the computer (there are two temperature sensors).
3. Try cycling the key on for two seconds and off before starting.
4. If it sat for months, drain and refill the gas tank.
5. Have spark and fuel checked before replacing parts.

Likely causes

1. Cold start injector or thermo time switch. The cold-start parts owners suspect first.
2. Faulty coolant temperature sensor. Wrong readings won't always set a code on these cars.
3. Fuel pressure bleed-off overnight. The key-cycle trick works around it.
4. Stale gasoline after storage. Members' top concern after six months of storage.

What it usually costs

No owner posted prices.

Is it safe to keep driving?

A cold sputter that clears when warm is usually drivable with care. Don't drive in traffic until it runs smoothly. Verify with a mechanic.

DIY or shop?

DIY-friendly for sensor and switch tests with a manual. Draining a tank is often easier at a shop.

Recalls, bulletins and complaints in plain words

• Recalls: NHTSA's recall lookup returned an error for the Toyota Supra for 7 model-year queries on 2026-10-26, so we couldn't confirm recalls here. Check your VIN at nhtsa.gov/recalls. If your car is part of a recall, the dealer fixes it for free.
• NHTSA complaints: 4 keyword-matched complaints for Toyota Supra 1986–1992 (of 36 unique complaints queried, NHTSA complaints API by model year, queried 2026-10-26; keywords: stall, start, cold, misfire, idle, sputter, fuel). This counts complaints that mention these words. It is not a defect finding.

What owners report

• In Missfire on a 7MGE Toyota Supra when cold on Car Talk, an owner said the Supra spits and sputters when cold but runs fine warm, and suspected the cold start injector or its time switch. A member with a 7M-GE '88 had the same problem and worked around it by turning the key on for two seconds and off before starting; others said to verify the coolant temp sensor and that the older computer won't flag a sensor sending bad data.
• In 1989 Toyota Supra - Hard starting on Car Talk, a Supra out of service for about six months over winter started for a short test trip, then the next day cranked but wouldn't start. Members suggested having it towed to a good shop and said gas left sitting six months may have gone bad and need draining.

Quick tip

If you store a Supra over winter, start with a near-empty tank and fresh gas in spring, or add stabilizer. It's cheaper than draining a tank later.

Vehicle focus: 1986.5–1992 Toyota Supra (7M-GE and 7M-GTE).

Safety / mechanic note

Don't use starting fluid repeatedly on these engines. Verify with a mechanic.