During engine warm-up the idle rpm is high (about 1000rpm). At normal operating temperature, rpm goes down about 200rpm. Also, when driving engine hesitate during acceration -- ignition timing is correct (12 deg BTDC)
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Re: Hesitation or stumble during acceleration
Take your car for a tune up if they are carburetor type motors you may need your carbie cleaned and a tune up if you clean it your self with carbie cleaner it may increase in idle speed this is nothing to worries about it is a simple adjustment with a carburetor type motor they tend to idle higher when their cold this is the automatic choke kicking in and normally it should happen till the car is a bit warmer and the accelerator has been depresses although a car should idle at 800 rpm my paddok car dose when it is cold it idles at 1200rpm i like it this way as the car warms up quicker as i will not drive a car while it is cold hope this helps ricko
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All the above is normal , except 2000rpm is a little high at idle . can be adjusted down to 1500rpm. the computer adjusts the engine speed . in drive the transmission loads up the engine idle drops to 1000rpm . in park engine unloaded rpm increase all normal.
Could be a defect in the ECU. But 1000rpm is not that high my cars normal is 1000rpm. but some older models were about 700rpm
The AC rise is normal. You may want to have a OBD II check by your garage or you can buy a unit to do this. It will scan the sensors fitted for any problems.
Yes, it is normal for a vehicles idle to be high when first starting up, no mater what the temp. If it`s already warmed up to operating temp, it will still have a high idle for a brief moment when starting. Usually this is the IAT (Intake Air Temperature) sensor. Located in the air duct down from the air filter, and before the throttle body.
Main proplems from IAT sensors are to low of an idle at normal temp, or the idle never comes down after warm up.
Your gas milage problems would stem from Oxygen sensors, plugs, wires, timing, etc...
Here is a quick test, just incase your OBD II (Computer, PCM..) memory module is not working properly. With the engine running, using the tips of your fingers, tap on the PCM, if the engine stumbles or stalls and sends troubles codes that light up your check engine light while tapping, if it does, check to make sure all wires are securely attached to it.
you didnt say if it was happening only during the initial warm up of the vehicle or all the time. if it is just during warm up this is not too unusual as long as the engine isnt racing. if it is just a "high idle", say arround 2,000 rpm's its normal. the idle would usually go down as the vehicle reaches operating temperature. when you put the vehicle in gear, you are actually loading the engine slightly, thats why the idle comes down then. when in park the engine has no load on it so it is free to rev a little higher at these times. if it a at a high idle constantly, then i would start looking for sticking throttle cable, binding throttle plates, ect and remedy the problem. this should not have anything to do with the dual exhaust.
First we would need to know when this occurs.
Asuming the oil level is at the full mark!. If the pressure goes up
during acceleration and down at idle when engine is fully warmed up,
then this is normal. An engine requires 10 psi of oil pressure per
1,000 rpm ( ex. 20 psi at 2,000 rpm, 25 psi at 2,500 rpm, and so on )
. If the gauge is moving back and forth erratically at idle , i would
say the gauge is bad. If it drops to 0 while accelerating I would say
your oil pump is bad. If from time to time it seems to work and other
times it seems not to work, I would say the oil pressure sending unit for the gauge is bad.
If the pump failed you would start to here a
Knocking noise from the engine in a short period of time. Use the
above scenario's to narrow down what it may be.
normal for an engine to start at elevated rpm and then die back as it takes a few seconds for the ECM doing it's sensor checks and idle back to the correct idle speed
check the idle rpm with an external rpm counter as most in dash units are inaccurate at rpm lower than 1000
as for the temperature
If you have a climate control module, it uses a mixture of heater and ac to maintain the temperature that you have set
so check it for operation
Offhand, yes this would be normal. The high idle is brought about by the auto choke whose purpose is to hasten the reaching of operating temperature of the engine. The fact that the idle RPM goes down after some time is a good indicator, it tells us that the auto choke is working.
Just a start, do postback how things turned up or should you need additional information. Good luck and Thank you for using FixYa.