Skip the auto shop - Our mechanics make house calls

Q: My car does not idle until it is warm. Can you tell me what's wrong?

asked by on

After doing my heads I put every thing back started the car and came up with a problem it does idle only when the car is warm it's low idle can you tell me what's wrong

My car has 19800 miles.
My car has an automatic transmission.

A: Hi there. Check the engine for any vacuum ...

Hi there. Check the engine for any vacuum leaks and see if all the sensors are plugged in. Take a vacuum gauge and put it on a vacuum line to the manifold. Check to see if the engine has 17 mg to 21 mg of vacuum. If the engine is less, then there is a vacuum leak and it needs fixed. If the vacuum is good, then look at all of the sensors and make sure that they are all plugged in. Also, make sure that the idle air control valve (IAC) is plugged in to vacuum and is working. If everything is working correctly and there is vacuum, then there is a possible issue with the IAC or the mass air flow sensor (MAF). If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from Your Mechanic, that can assist you with the engine idle not staying up during startup.

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!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Security system keeping my vehicle from starting.

Hi there. Try turning on the ignition switch for 5 seconds then turn it off, but do not start the engine. Do this step 3 times and then the computer will acknowledge the key chip and should allow you to...

Q: Engine light comes on and idles roughly.

Single cylinder misfires are usually caused by ignition components which is where I would start with on this car. Verify the ignition cap and rotor are still in one piece and that the wires are not arcing losing spark. Have...

Q: Car will not idle

If the car will not idle then you may have a carburetor mixture problem or ignition timing and distributor problems. If the carburetor needle and seat is leaking, it may be flooding the engine at idle. I recommend having a...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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.
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.