A weak idle is most often caused
by vacuum leaks in the intake system.
If the idle control valve is good then the problem is typically caused
by a vacuum leak or an issue with the throttle body.
Usually a high engine idle is caused
by a vacuum leak.
Not exact matches
Hyperloop gets around this major issue
by only having a partial
vacuum in the tubes (meaning they can
leak a little).
Documents
leaked by Snowden showed that the National Security Agency went much further
by vacuuming up huge troves of email and other digital data.
But maintaining this partial
vacuum in an industrial plant is difficult, and up to 25 per cent of the magnesium vapour may be reoxidised
by air that
leaks into the system.
Be aware though, that the
vacuum test done
by A / C machine doesn't necessarily find a
leak unless it's big enough.
That won't tell you were the
leak is (unless it's huge and you can hear the air getting back into the system), but it will tell you if you have one, and it will also give you an idea of the size of the
leak (
by how fast the
vacuum is lost).
You can test for the presence of a
leak without expending any R134a
by sucking the system down to a
vacuum.
This could be cause
by a small
vacuum leak or
by a dirty air filter or mass airflow sensor (MAF).
Did you check your
vacuum lines, IDK about your specific vehicle, but on some cars the climate control is powered
by vacuum and a
vacuum leak will cause them to operate / fail intermittently based on engine load.
If it's neither of these things then it could conceivably be a
vacuum leak caused
by a split pipe or perished rubber seal somewhere on the inlet side of the fuel system.
Start a
vacuum -
leak smoking expedition
by plugging up any obvious potential ports in the intake manifold, starting with the inlet to the throttle body from the air cleaner.
The EPA started to require that
leaking gasoline fumes be reduced to virtually zero, and the EVAP system on every current car is controlled largely
by — you guessed it — engine
vacuum.
In most cases, the issue of «self acceleration» is caused
by one of the following; a damaged throttle body,
vacuum leak, electronic throttle control, or idle control valve issue.
A rough idle (https://www.yourmechanic.com/services/car-idle-is-rough-inspection) may be caused
by things such as low fuel pressure, low voltage to the fuel injectors, dirty fuel injectors, a
vacuum leak, a faulty...
This could be caused
by a cold state
vacuum leak.
You may need to have additional diagnosis done
by a mechanic like one from YourMechanic to see if the ignition timing is correct and there is no engine
vacuum leaks in the intake or
vacuum lines.
Fuel related misfires can be caused
by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air - flow sensor, a faulty or dirty idle air control valve or a
vacuum or intake
leak.
The lack of response to the accelerator pedal has quite a few potential causes that would have to be sorted out in a diagnostic including, just as a few examples, plugged fuel injectors, faulty oxygen sensors, fuel pump and / or filter,
vacuum leaks including that caused
by a faulty EGR system, ignition system malfunctions, bad valve timing if the timing belt or chain is worn or skipped, blocked exhaust (e.g., catalytic converter fails or becomes clogged), a faulty airflow sensor or throttle position sensor, and so forth.
Loss of power on acceleration can be due to plugged fuel injectors, faulty oxygen sensors, fuel pump and / or filter,
vacuum leaks including that caused
by a faulty EGR system, ignition system malfunctions, bad valve timing if the timing belt or...
Rough idle can be caused
by dirty fuel injectors, incorrect idle speed, exhaust restrictions,
vacuum leaks, incorrectly installed or damaged spark plugs, a defective or clogged fuel pump or fuel filter, failing electrical components such as the ignition control module,...
In a more technical jargon,
vacuum or intake
leaks are called «unmetered air», as the air enters the intake system through a damage intake boot or other
leak is not metered
by the mass air flow sensor and therefore the the engine computer can not calculate the amount of fuel injected properly, causing the engine to run «lean».
That being said, unauthorized disclosures
by the former are already occurring, but they are occurring in a complete legal
vacuum where people like Snowden have less of an incentive to be careful with the scope of their disclosures since they know they are already facing either jail time or exile regardless of the public value of the
leaked information.