Skip the auto shop - Our mechanics make house calls

Q: RPM running high in neutral

asked by on

Rpm ( tachometer) suddenly started running overly high ( marked 3) , and it will stay like that in neutral.

My car has 200000 miles.
My car has a manual transmission.

High idle can be caused from several things. Your Saturn’s extremely high idle is likely being caused by air leaking into the intake manifold. It’s called a vacuum leak. This can be caused by a hose that has fallen off or deteriorated with age. An intake manifold gasket can also leak, which allows extra air into the engine. The computer senses the extra air, adds fuel to match, and suddenly you have a high idle speed. A problem with the engine coolant temperature sensor can also lead to fast idle if it’s mistakenly telling the computer that the engine is very cold. There is also a component called the Idle Air Control (IAC) that the computer uses to meter the correct volume of idle air into the intake manifold. The IAC may be dirty, stuck, or broken from old age. A certified mobile mechanic from YourMechanic can visit your home or office to inspect why your vehicle has a high idle and provide any necessary repairs.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. RPM running high in neutral

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: How much will it cost to replace CV Joints or struts on 96 Saturn?

Hi there. The clicking or popping sound when turning is the sound of the outer ball joint in the CV Shaft that is emitting the sound. The joint is either worn or out of lubrication and trying to seize up....

Q: Battery shot?

I would not recommend using jumper cables as a means to connect your battery for a couple of reasons. First of all, it can be dangerous as it can create additional risk of sparks that would not otherwise happen when...

Q: Water pump squirting out water

It would appear that your water pump has sprung a gasket leak, and is leaking coolant. As coolant leaks can lead to overheating and engine damage, I would recommend having the leak addressed as soon as possible. A professional technician,...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.