Troubleshooting Fast Idle Problems
If the PCM offers no hints, the best place to begin looking for problems is with the Idle Air Control Valve/Bypass Air Control (IACV/BAC). You can try cleaning it and see if that improves your idle speed. A
throttle body cleaning
is likely to cure the high idle speed as well.
What causes a car to idle very high?
When your car’s throttle is malfunctioning
, this can cause your car to stall or idle high. Often this is a result of dirt buildup in the air intake. Other times it can be a problem with a cracked intake tube. If the IAC motor’s vacuum port is leaking, this can be another cause of high engine idling.
Why does my car idle high after it warms up?
If your engine seems to be overheating in addition to the higher idle speeds, there could be an issue with your engine’s cooling system and/or
fast idle control system
. … If this system is not functioning properly, the fast idle could remain on even after the engine is warm causing it to overheat.
Can high idle cause damage?
Plus, excessive idling
can damage your engine’s components
, including spark plugs, cylinders and exhaust systems. Because your vehicle’s engine is not operating at its peak temperature when idling, fuel is only partially combusted, leading to a fuel residue buildup on cylinder walls.
Is it normal for a car to idle high when cold?
High
RPMs in the cold is a result of combustion taking place in the engine. Your car is able to start because gasoline and air are coming together to form a spark. … Gasoline vaporizes much more easily in warmer temperatures to get that spark. In colder temperatures, fuel is more likely to get bogged down and thicken.
Does high rpm hurt engine?
While extremely low rpm and high loads will damage your transmission right away,
sustained high rpm may damage it over the long run
. High rpm means more wear on the bearings and oil seals, and quicker transmission fluid breakdown.
What is considered high rpm?
How many RPMs is too high? Typically, engines idle at about
600-800 rpm
. Older engines may go up to 1200 rpm or more while warming up. But if the engine is revving up while idling, even after it’s sufficiently warmed up, you might have a problem.
Can a bad fuel pump cause a rough idle?
What to Look For: A bad fuel
pump can cause difficulty when starting the vehicle
, a rough idle, and stalling. Clogged Fuel Filter – The fuel filter filters the contaminants from gasoline. Over time it can become clogged, which slows the flow of fuel.
Can a dirty air filter cause high idle?
It is just as important for your engine to get enough air, as it is for it to have enough fuel. A
clogged filter will reduce the flow of air into the engine
, causing a rough idle. It may also increase your fuel consumption.
How much does it cost to fix a high idle?
The replacement cost of an idle control valve is anywhere from
$120 to $500
. The cost of the parts alone will be between $70 and $400+, depending on the make and model of your vehicle. The labor cost should only be around $50 to $100 because it doesn’t take that long to remove and replace the old idle control valve.
How do you fix high idle after cleaning throttle body?
The idle will relearn if you put the vehicle in drive and allow the idle to come down with all accessories off for about two to three minutes.
Then turn on your a/c with blower in high position for
three minutes. This should fix it.
Can bad spark plugs cause high rpm?
Improperly functioning spark plugs
cause an uneven burn of fuel in the engine, resulting in fluctuating RPMs and a louder noise. You might also experience increased vibrations of your vehicle while sitting idle or while traveling at low speeds.
What RPM should a car idle at?
For regular cars, idle speed is typically
between 600 and 1,000 rpm
, just enough to keep the engine’s ancillary systems going, but not enough to move the car forward much.
How do you know if you have a vacuum leak in your car?
- Your Idle is Running High or is Sporadic. Your engine’s RPM goes up as more air cycles through your engine. …
- Stalling or Hesitating Engine. …
- Loud Hissing, Squealing or Sucking from the Engine.
What RPM should my car be at 70mph?
Make sure your OD is on,
3000
seems fine for 70. The motor needs to work harder if you go fast.
What RPM should my car be at 60mph?
It does
between 2,000 and 2,100rpm
at 60 mph.
