High RPM & Blinking Preheating Light?

Sure, here is the translation of the text from German to English:

'All' translates to 'all' in English.

I'm having the following problems with my Golf IV, manufactured in 1998, 1.9L engine, 110 horsepower (all original), with 117,000 km on the odometer. I plan to take it to the workshop next week, but I wanted to hear your opinions first.

'The idle speed occasionally increases to around 1050 RPM, and eventually it drops back down – this only happens when the engine is warm. However, if I'm, for example, stopped at an intersection and notice the RPMs are rising, and then I press the accelerator to increase the RPMs to around 3000, the idle speed then returns to the normal level. But this doesn't always work. Most of the time, the engine then stays at the described 1050 RPM. If I then turn off the engine and restart it, it continues to run at a higher-than-normal RPM.'

2. Just before I parked the car today, the preheating light suddenly started flashing. However, the engine continued to run normally. I then turned it off and restarted it, and the light stopped flashing. According to the manual, I should urgently take it to the workshop in this case .

3. It's probably not an engine problem, but still: When I'm driving around a curve, whether it's to the right or left, and braking at the same time, something squeaks (it's not tire squeal ). But it only squeaks in combination with braking, turning, and road bumps.

What are your thoughts on these issues?

Thank you.

If the preheating light is blinking, I would suggest checking the error memory of the engine control unit (ECU). There might be more information that can be derived from it.

'The idle speed occasionally increases to around 1050 RPM, and eventually it drops back down – this only happens when the engine is warm. However, if I'm, for example, stopped at an intersection and notice the RPMs rising, and then I floor the accelerator to increase the RPMs to around 3000, the idle speed then returns to the normal level. But this doesn't always work. Most of the time, the engine then stays at the described 1050 RPM. If I then turn off the engine and restart it, it continues to run at a higher-than-normal RPM.'



Coolant temperature sensor or throttle position sensor: Implausible signal.

Probably the temperature sensor... -> The diagnosis will provide more information.

CU.