What's the matter with high fuel consumption and low idle speed in Mitsubishi Golan?

The gasoline added has the wrong label, poor quality, etc.

The air-fuel ratio is unreasonable, which may be caused by some sensors not working well or carbon deposition in the throttle.

There are many reasons.

There is carbon deposit on the piston of the valve cylinder, and the fuel is partially absorbed by the carbon deposit.

Wrong label of added lubricating oil, quality problems, etc.

The cylinder leaks air and the ignition time is not equal.

The air filter is blocked, or the exhaust three-way catalyst is blocked, resulting in poor air intake and exhaust.

The belt connecting the water pump, oil pump and generator is too tight, which leads to increased running resistance.

Probably these problems, I suggest you go to the repair shop to check, after all, high fuel consumption and cost-effective repair; I hope I can help you.