Skip the auto shop - Our mechanics make house calls

Q: Mass Air Flow replacement and problems with a fast idle

asked by on

Changed the maf and truck is idling way too fast, cleaned old maf and put it back in and still idling way too fast

My car has 160000 miles.
My car has an automatic transmission.

A: This may be related to a dirty or faulty id...

This may be related to a dirty or faulty idle air control valve. As you may know, this works similarly to the mass air flow sensor in that it relays air information to the computer which then makes adjustments to fuel based upon this information. The idle air control valve, however only operates at low speeds and at idle. This allows the proper air/fuel mixture to happen at idle and also when the engine rpm's are decelerating from a higher rpm.

When this is not working properly, this may cause an erratic idle as you have described. This may also be caused potentially by an intake air leak or a vacuum leak as this will create a lean fuel condition also causing a higher idle speed.

To avoid any unnecessary repairs, I would recommend having an expert from YourMechanic come to your location to diagnose your high idle condition and service your idle air control valve as necessary.

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: My Jeep started fine. I adjusted the tilt steering. The airbag light came on but it continued to run fine. Shut Jeep off and would not start again

The air bag light comes on when the computer detects an issue with the vehicle's air bag safety system. This can have many potential causes, including a faulty sensor, wiring, air bag unit, computer, among other things. If you were...

Q: I just replaced my brake master cylinder and the brakes still feel soft. What do I need to do after I replace the master cylinder

From what you've described you will have to bleed your brakes. Also, I believe you may have a leak in one of the lines. You may want to use a wrench and tighten the lines a little more. If you're...

Q: Car won't stay crunk

This may be a result of a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and...

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...
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.