Sit in the driver's seat when you buy best quality Used Cars in Kenya and start the engine. When the engine is idling, the vehicle should not jolt, vibrate intermittently, and blue smoke should not emerge from the exhaust when you press the accelerator pedal. These two issues indicate that the vehicle's engine oil may be dirty and internal parts of the engine may be worn. You may encounter these problems mostly when you want to buy a vehicle directly from the owner. What do you think?