Skip the auto shop - Our mechanics make house calls

Q: Ignition takes longer and idle goes higher after ignition

asked by on
  1. Sometimes, not always, when I hit StartEngine button, it would take about 2~3 sec. to start (normally it is instant-start).
  2. After the ignition though, it happened only once, the idle went up to 1500 rpm, which it normally is around 700~800 rpm. I was stoned for about 4 sec. and I then shifted from P to D, and the idle went back to normal right after I shifted the gear. I live in San Diego, and it is not like freezing cold even in Winter. At night the lowest temperature is around 44.6 F.

My car has 17800 miles.
My car has an automatic transmission.

This may be a sign of a vacuum leak. High idle speeds or in some cases rough idle, stalling and hissing sounds are common signs of a vacuum leak. When a vacuum leak is present in an engine, this causes an excessive imbalance in the air/fuel ratio which creates a loss of power and causes the motor to run at a much higher RPM as a result of the increased oxygen present in the fuel charge being injected into the motor. The excess air present in the system while starting may also cause the slight delay in starting as the system struggles to find the correct air/fuel balance. I would recommend having an expert from YourMechanic come to your location to diagnose your vacuum leak as these can be very difficult and time consuming to trace.

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. Ignition takes longer and idle goes higher after ignition

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: serpintine belt and tensioner pulley replacement.

Hello. Thanks for writing in. Obviously you will want to clear some room to have access to the tensioner. This is easiest done by removing the radiator. Once you have the old tensioner removed, you simply reverse the process to...

Q: 2011 Audi s5 3.0 hard starting after gassing up

Hello, thank you for writing in. There are many factors to consider in these situations. If your vehicle was run very low on gas, you may have sucked up debris from the fuel tank into the fuel system. You can...

Q: Air conditioning and heater will turn on sometimes.

Check the wiring from the motor switch to the a/c and heating selection. Either the wiring is loose and is moving around causing the system to not operate properly or the switch has failed. If you need further assistance with...

Related articles

P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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.