Question: Why Does My Jetta Idle Go Up And Down?

What should rpm be when stopped?

The idle speed should feel consistent without skipping or slipping.

In most of today’s cars, an idle speed of 600 to 1000 RPMs is average.

If your car is idling rough, though, it won’t feel smooth.

The RPMs will jump up and down, for example, or they’ll fall below 600 RPM (or whatever is typical for your vehicle)..

How do you fix a surging idle?

The cure for this condition is to clean the valve with some aerosol throttle cleaner or engine top cleaner. Here’s how to clean the IAC valve: Disconnect the air intake ductwork from the throttle body. Start the engine, then increase and hold the idle speed to 1,000 to 1,500 rpm.

How much does it cost to replace the idle control valve?

The replacement cost of an idle control valve is anywhere from $120 to $500. The cost of the parts alone will be between $70 and $400+, depending on the make and model of your vehicle. The labor cost should only be around $50 to $100 because it doesn’t take that long to remove and replace the old idle control valve.

What causes idle to go up and down?

Erratic engine idle can be caused by various factors, but the most common and likely cause is a dirty or malfunctioning Mass Air Flow (MAF) sensor. This is a device found in fuel-injected cars and measures air flow so that the appropriate amount of fuel can be injected.

How do you fix a surging engine?

A faulty fuel pressure regulator an cause low fuel pressure, leading to engine surging. The fix: These are generally not easy DIY jobs. Check fuel pressure with a fuel pressure gauge. If low, take it to a mechanic, as repairing or replacing a fuel pressure regulator.

Why is my rpm going up and down in park?

The idle is controlled by the idle air control valve and if it cannot keep the engine idling it will keep trying to rev the engine up to compensate. A vacuum leak, sensor that has failed, or an EGR system malfunction could potentially be the cause of the erratic engine you’re experiencing.

Does high rpm hurt engine?

If you rev your engine to high RPM on occasion and only keep it there for brief periods of time, generally this is not going to cause much damage to the engine. … High RPM causes more wear on the engine components than lower revs. Every engine has a point where it will come apart internally at a certain speed.

Is revving in Park Bad?

Answer is….its ok to rev you engine in neutral/park. Just not when its cold and dont hold it on rev limiter! Try not to, because free revving can damage the engine.

Why does my car rev up and down by itself?

It sounds like you may have a dirty or failing idle air control valve. … This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage.

Where should the RPM be at idle?

For a passenger car engine, idle speed is customarily between 600 and 1000 rpm. For medium and heavy duty trucks, it is approximately 600 rpm. For many single-cylinder motorcycle engines, idle speed is set between 1200 and 1500 rpm.

What causes rough idle when warm?

How To Fix Rough Idle When Warm? Most likely, the causes of rough engine idle crops from the basic functional components like direct fuel injectors, PCV valve, EGR valve, Oxygen sensors, vacuum leaks, air filter, and spark plugs or wire.

Is it normal for RPM to fluctuate at idle?

It actually is completely normal for the engine idle speed fluctuate a small amount. … That is a lot to ask the engine to do at a very low rpm.

What are the symptoms of a bad idle control valve?

Usually a bad or failing idle control valve will produce a few symptoms that can alert the driver of a potential issue.Irregular idle speed. One of the most common symptoms associated with a problematic idle air control valve is irregular idle speed. … Check Engine Light comes on. … Engine stalling.

How do I reset my idle air control valve?

How do you reset the IAC valve?Depress the accelerator pedal slightly.Start the engine and run for 5 seconds.Turn the ignition switch to the OFF position for 10 seconds.Restart the engine and check for proper idle operation.

What causes engine to over rev?

If an engine goes overspeed, commonly called “over-revving”, damage to the piston and valvetrain may occur when a valve stays open longer than usual. Valve float can possibly result in loss of compression, misfire, or a valve and piston colliding with each other.

What should my rpm be at 70?

RPM of the engine depends upon its size and largely on gearing ratios. Two cars of the same make with different engines will have different RPM at 70mph. Car with more number of gear and higher engine displacement will have lower RPM. … Generally, the average car stays at about 2500 rpm while doing 70mph.

How do you test a idle control valve?

How to Check an Idle Air Control ValveOpen the hood and remove the screws holding the idle control valve to the throttle body on the back of the engine.Unplug the electrical plug running to the control valve. … Pull the idle control valve off the throttle body and turn it over to expose the valve openings.Turn the dial on the voltmeter to “Ohms.”More items…

Why does my truck rev up and down while driving?

Transmission slipping, or gears slipping, is a common transmission problem and a real cause for concern. … If your engine revs up as you press down on the accelerator but your vehicle doesn’t accelerate as per usual or as you would expect, it’s a troublesome sign that can lead to a full-blown transmission failure.