Why is there a raw fuel smell and rough idle when stopped?
When a warm engine idles for a short period and begins shaking while emitting a strong raw petrol smell from the exhaust, it indicates unburned fuel entering the exhaust system. This leaves drivers unsure of where to start diagnosing the issue or how to prevent potential damage.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Keeping the car parked until it is fixed to avoid risking damage to the catalytic converter or diluting the engine oil.
- 2Checking for fuel leaks or replacing the fuel line.
- 3Taking the car to a mechanic or shop ASAP
- 4Fixing a leaking valve cover and changing the oil
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'm having a concerning issue with my 2010 BMW 116i E81 (N43B20 engine) and could really use some diagnostic advice.”source ↗
“When the engine is warm and I come to a stop (e.g. at a red light), the engine starts shaking mildly and after about 20 to 120 seconds of idling.”source ↗
“Immediately after stepping out, there is a strong smell of petrol coming from the exhaust / rear of the car.”source ↗
“I started noticing this burning smell and this is what i found. Don’t know why its happening or where to start with fixing it.”source ↗
Where this came up
People with this problem also raised
- 5Engine smoke and burnt coolant smell while driving
- 2Strong gas smell in room after new pipe installation
- 3Car shaking and burning smell while driving
- 2Why is my car blowing oil smoke from the exhaust at startup?
- 2Why does my garage smell like cigarette smoke when nobody smokes?
- 4Grinding noise and smoke from under the car hood