how long until gas goes bad in denver
Gas usually goes bad in about 3 to 6 months in a car, and ethanol-blended fuel can start losing quality in 1 to 3 months ; heat can speed that up, so Denver’s dry climate doesn’t really make gas last much longer on its own.
Quick Scoop
If your gas has been sitting in a tank for a few weeks, it is usually still fine. If it has been sitting for a few months, especially more than 90 days , the risk of rough starts, poor running, or stale fuel goes up.
Signs it may have gone bad
- Sour or varnish-like smell.
- Darkened fuel or visible debris.
- Hard starting, rough idle, knocking, or stalling.
- Worse fuel economy or a check engine light.
What to do
- If the fuel is only a little old, top it off with fresh gas to dilute it.
- If the car sat for a long time, a mechanic may need to inspect the fuel system.
- For storage, keep the tank fuller, use fuel stabilizer, and run the car periodically.
| Situation | Typical risk |
|---|---|
| 2–4 weeks old | Usually fine |
| 1–3 months old | May start to degrade, especially ethanol blends |
| 3–6 months old | Common window for stale gas |