Why is my car running rich and smoking after sitting for years?
Vehicles left sitting for extended periods often suffer from degraded fuel, stuck injectors, or saturated components that cause them to consume excessive fuel and produce heavy smoke upon startup and throttle. This severe richness creates a strong fuel odor and prevents normal driving operation.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1performing a smoke test to check for leaks
- 2checking fuel injector operation and pressure
- 3inspecting mass airflow sensors and spark plugs
- 4capping off the purge solenoid hose
- 5borrowing a scan tool to monitor fuel trims
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“I have a 02 f150 4.6 v8 and it’s running too rich it’s eating gas like crazy and it hasn’t even left the neighborhood, when turning the car on the white smoke slowly gets worse, the smoke is even worse when you give it throttle.”source ↗
“Really don’t know what may be the issue. Also the truck had been sitting for about 5 years before we bought it.”source ↗
“This is my 2016 Cadillac CTS 3.6 140k miles. The car recently started developing a crazy fuel odor out the exhaust. Under heavy throttle, it will release a plume of dark grayish smoke.”source ↗
Where this came up
People with this problem also raised
- 7Dealership can't figure out why my car won't start
- 16Why does my car engine cut out after driving for a while?
- 10How to get a rusted suspension part unstuck
- 11Why does my car lose power for a second when starting?
- 21Intermittent car hesitation with no trouble codes
- 107How to explain an intermittent car noise to a mechanic