Q: Car idles at high RPMs

asked by on

My car has manual transmission. It has gone around 140,000 miles. I've been having some issues with high idling for more than eight months. When I drive it for a short while, it would start revving at high RPMs, over 2800 while it idles. It helps somewhat if I restart it quickly. This is happening with increasing frequency and at even higher RPMs. The dashboard doesn't show any lights on. What could be causing this?

Idling too fast can be caused by several things. But bottom line is that too much air is getting into the intake manifold. Manifold vacuum leaks are a common cause. Do a visual inspection to check for any vacuum hoses that are broken or fallen off.

There can be several possible causes for this. The intake manifold gaskets may be leaking. The power brake booster can be leaking - pinch off the big vacuum hose to eliminate that. A dirty throttle body can be preventing the throttle plate from returning to its closed position. The Idle Air Controller (IAC) can be sticky or failed. The Engine Coolant Temperature sensor circuit can be faulty making the Powertrain control module (PCM) think that it is freezing cold outside which requires a fast idle. Have the high idling issue diagnosed by enlisting a certified mechanic to visually inspect, test, and scan your car.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Car idles at high RPMs

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car revs in drive, doesn't move.

With the car warm parking brake set and in park (automatic) neutral (manual shift) while on level ground check the transmission fluid level, it should be within the hashmarks. If it's low this could be your problem, the amount of...

Q: Q: Car will turn over but not start.

Hi there. You will need to add a pint of fuel water vaporizer to the fuel tank. There is excessive water in the fuel system and that is why your exhaust is white is if there was water in the...

Q: Replaced battery. Car still won't start. Gas meter reads empty after filling with fuel.

Hi, thanks for writing in. This can happen for many reasons and without further detail may be difficult to diagnose without performing a physical inspection of the car and diagnosing using a scanning tool. I would recommend having an...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.