Car inspection failed due to environmental standards. The engine's maximum idle speed doesn't reach 5000 RPM. Can anyone advise on what to do?

When driving the 2014 Foton Tunland 2.8S 4WD, there is a noticeable humming vibration in the cabin when the alternator speed is below 1600 RPM. However, once the engine speed reaches 2000 RPM, the humming sound disappears. Could any experts advise on what might be causing this issue?

What's the idle speed of your Mazda 3 when starting cold? Mine is over 1000 RPM.

Is anyone familiar with solving the issue of idle speed occasionally rising to 2000 RPM and then dropping back down on a stock MG HS? It's particularly noticeable at low speeds.

When starting a cold car, the RPM goes up to 2000 and then drops to 1500 but doesn't go any lower. The high idle speed is causing high fuel consumption, 20 liters for 300 kilometers! The idle speed is too high, and so is the fuel consumption. Can any experts provide a solution? 🙏

When I start the car, the idle speed is around 2000 RPM, but after a while, it drops to 1500 RPM. It takes quite a long time to go down to around 1000 RPM. Does anyone know what's going on?

Why is the idle speed around 600 to 700 RPM?

I just got the Middle East 5.6, and I noticed that in daily use, the car mostly runs at idle speed, not even reaching 1500 RPM at 100 km/h. Will long-term low RPM driving lead to carbon buildup? I need advice from experienced experts.

The Volvo C30 2.0D has a normal idle speed of 850±20 RPM when in gear, but the idle speed is high at 950±20 RPM when in neutral. What's going on?

Help needed, fellow Peugeot owners! Ever since my little Peugeot went on a continuous uphill drive for over an hour a few days ago, it's been having issues. The RPMs go up, but the speed doesn't. It's not too bad when not on the highway, as pressing the accelerator quickly gets the RPMs and speed up. But once I'm on the highway and going over 80-90 km/h, I need to press the gas to at least 2000 RPMs for the speed to increase very slowly. On inclines, if I don't reach 2500 RPMs, the speed drops. I never had to go over 2000 RPMs on the highway before. What's going on? 🌹

After refueling my Jetta VS7 at the gas station, the idle speed tends to be high, around 1000 RPM. Then, during driving, the speed fluctuates. After driving for about ten kilometers, the idle speed returns to normal. Alternatively, if I turn off the engine and restart it, the idle speed also normalizes. I've tested this each time I refuel, and it's always the same situation.