Idle problem

2003 HONDA CRV
202,000 MILES • 4 CYL • 4WD • AUTOMATIC
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GARYWCRANE
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After driving for about an hour in hot weather, 88 mph and above, the engine idles at 1,500 to 2,500 rpm's, shifter will not shift. Sometimes when I put 1/2 quart of oil in it and let it cool down a while, it will do fine afterwards. What is the problem?
Jun 29, 2020 at 5:56 PM
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JACOBANDNICKOLAS
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Hi,

The idle can be related to a few things. For example, an engine vacuum leak, faulty idle air control system, engine coolant temperature sensor and so on. However, I'm a bit confused on the shifter. Do you mean it physically doesn't move?

As far as the idle, it is controlled by what is called an idle air control valve (IAC) which is located on the throttle body. After the engine starts, the IAC valve opens for a certain amount of time. The amount of air is increased to raise the idle speed. When the engine coolant temperature is low, the IAC valve is opened to obtain the proper fast idle speed. The amount of bypassed air is controlled in relation to engine coolant temperature.

Now, I attached a pic below of the IAC system. Here is a link that explains in general how one is serviced. You may want to start with this.

https://www.2carpros.com/articles/idle-air-control-valve-service

Also, let me know if the check engine light is staying on with the engine running and if you have ever noticed any issues with the temperature gauge in the vehicle.

Joe

Jun 29, 2020 at 9:51 PM
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GARYWCRANE
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Not the IAC. Still doing the same thing. The car has been running hot lately when this happens. I use the vehicle to deliver mail on an auxiliary route, about 2.5 hours.When I stop, add a little oil sometimes, let I cool down for maybe 10 minutes, it does well the rest of the route. Thanks for your help. Hope you have more suggestions.
Jul 5, 2020 at 3:37 PM
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JACOBANDNICKOLAS
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I have to ask if what you listed above was a typo. You indicated after, "After driving in hot weather for an hour, 88 mph and above..." Do you mean degrees?

As far as it running hot, is the coolant full? Have you noticed if the cooling fans are turning on?

Back to the idle issue, have you checked for engine vacuum leaks? Here is a link that explains how it's done:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Also, did you replace the IAC? How often do you have to add oil?

Let me know.
Joe
Jul 5, 2020 at 8:43 PM
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GARYWCRANE
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Yes, 88 degrees. Will check for leaks. Thanks. Coolant is full. Fans run. Replaced IAC, add about 1/2 quart of oil each week maybe.
Jul 6, 2020 at 5:50 AM
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JACOBANDNICKOLAS
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If the coolant is full and the fan is working, suspect the thermostat needs replaced. I would also flush the cooling system when replacing the thermostat.

Here are two links related to replacing the thermostat and flushing the cooling system:

https://www.2carpros.com/articles/replace-thermostat

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

______________________________

Here are the directions specific to your vehicle. The attached pic correlates with the directions.

2003 Honda Truck CR-V 4WD L4-2.4L
Procedures
Vehicle Engine, Cooling and Exhaust Cooling System Thermostat Service and Repair Procedures
PROCEDURES

Pic 1


Thermostat Replacement
1. Drain the engine coolant.
2. Remove the splash shield (see step 22).
3. Remove the lower hose, then remove the thermostat.
4. Install the thermostat with a new O-ring, then install the lower hose.
5. Install the splash shield (see step 23).
6. Refill the radiator with engine coolant, and bleed air from cooling system with the heater valve open.

___________________________________________

Let me know if you are able to find any vacuum leaks.

Take care,
Joe
Jul 6, 2020 at 9:41 PM