When you turn the ac on it engages the ac clutch which is turned by a fan belt which is turn by the engine. you are making the engine work harder. The idle speed might be set to low or it,s time for a tune up.
What causes back firing on a ford explorer and it to idle rough and want to cut out when you try to give it gas.
The most common reason for an engine not to start is a lack of fuel. A plugged air filter can cause and engine to idle rough or not idle at all.
Might want to check your idler sensor.
idle speed controll or tps throttle sensor
I have a 97 Hond Accord I just bought and it was idling at 1500 rpm standing still in park. You can adjust the idle by adjusting the throttle cable at the throttle body. There is two nuts on each side of the bracket, loosen both and slide cable until you reach 900 to 1000 rpm range or if you want higher idle adjust it up. If that doesnt fix it check for a vacuum leak. They will also cause your engine to idle higher.
A vacuum leak would do that. Check the base gasket under the throttle body.
I am a certified aircraft powerplant technician, and owner of a 2006 Honda Civic Si. As with all internal combustion engines, it is considered normal for an engine to idle "high" during a cold start up. During this period, the oil is coming up to optimal temperatures, coolant is beginning to flow through the crank case, etc. In my personal experience with my Si, my vehicle will idle at about 1500 RPM for a good minute before it begins to drop to a normal (engine warm) idle speed of 800 RPM. However, if you are experiencing idle speeds in excess of 2500+ RPMs during a cold start, or your vehicle demonstrates this high idle when your engine has been running for over 5 minutes, you may want to take your vehicle in to be examined.
Turn the idle nob on the ecu counter clockwise a little until you get the idle you want.
You will want an idle speed between 750 and 900 rpm with the ac on and in gear (if auto).You will want an idle speed between 750 and 900 rpm with the ac on and in gear (if auto).
With the engine running, turn the idle screw until you get the speed you want.
prob around 600 if you want a lump idle to 750 - 800
your engine will sound rough while at idle speed and your gas milage will start getting worse. it also might start to backfire and make a little more noise than it normally would.