Probaby a sensor.
the engine to stall and surge at idle
the surge the engine does when you first start it up is normal, the engine is built to do that to assist with warming up the system it should lower after 30secs or so.
Your 1994 Honda Civic will overheat when the thermostat is malfunctioning. The overheated engine can experience the idle to surge. The engine should be turned off immediately.
Have you tried replacing the hose for the automatic choke if it has one as mite not be getting enough air in and so is surging.
The first things to check are the air intake, the fuel pump/filter and the governor.
auto or stick shift
At idle or low engine idle speeds you motor may surge. This could be caused by an air leak in your intake manifold or a bad sensor like a TPS or MAP.
The idle control valve works by regulating the idle speed of the engine. The idle speed of the engine is usually controlled by the engine of the computer.
i dont know mine does only at idle and i think i have a weak coil for 2 and 5 on my 95. or your idle air control vacuum motor
There are just too many of the one or two of the devices on the car that would be causing this. Go to a tune-up shop.
if surges worse at idle when cold possible intake manifold gaskets leaking will usually set o2 or fuel trim codes
If its computer controlled engine, it more than likely a dirty or bad Idle Air Control Valve.
Your check engine light will be on and you will feel bucking or jerking while you are accelerating. You will also have an idle surging, sudden stalling of the engine, and a sudden surge in speed while driving on the highway.
the Vaccume Brake Booster is bad.
Clean the MAF sensor with CRC MAF cleaner, do not touch the sensor wires, you'll damage the unit and freah is ~ $175.00
because that's kind of a big engine
The Idle Speed misadjustment, Timeing misadjustment, or bad throttle position sensor. Search one of the 4WD forums like IH8MUD.com or Pirate4x4 for idle surge. check the coolant level.
Mine was doing that for a while. I took the Idle Air Control valve apart and cleaned it. Problem solved. Its normal for the engine to idle higher when its cold though. Once it warms up a bit the idle should settle down.
My guess is it will causes the engine to surge and change engine speed up and down over and over because the ECU (computer) is searching for the right idle speed, but the bad sensor isn't sending the signal. It could also possibly cause the engine to just idle at a higher speed than normal.
does the engine have a carburetor or is it fuel injected? A carbed engine has mixture screws along with a base idle screw, a fuel injected engine the idle is computer controlled.
A failing throttle position sensor is a common cause for idle speed fluctuations on a Jeep 4.7L.
maybe the clutch
I had the same problem and it turned out to be the fuel purge censor
Since it is starting from 0, the engine idle is low.