Generally a surge at low RPMS is caused by a defective vaccum componet or a cracked vaccum line. It still leaks at higher speed but you don't notice it because the engine is GENERATING more volume of vaccum to cover it up. Try this: Take some WD40 and lightly spray it around vaccum lines while the motor is running; as soon as the engine smoothes out you have found the troubled part. The wd40 will TEMPORARILY seal the leak.
IAC (Idel Air Control Valve)
Is the AC turned on?
There can be many reasons why a car surges while idling. Some of these reasons are the computer could be dying, or the fuel injector are giving the engine too much gas.
I think I'd check for a loose, cracked or missing vacuum hose somewhere under the hood. FriPilot
There are several things that can cause your Jeep to stall while idling. The timing may be off or your fuel filter may be clogged.
The spark plug gap can cause the RPMs to fluctuate, while idling. The more probable cause of the fluctuating RPMs is a bad camshaft.
Engine miss.
No, very doubtful.
The most likely cause of a 1992 Ford Aerostar stalling while idling is bad spark plugs. The plugs should be changed and the timing checked to resolve the problem.
Best guess without actually touching the vehicle would be the voltage regulator. on most cars this is part of the alternator. I would start by checking the voltage on the battery while the car is idling and while running ~2000 rpm
If its computer controlled engine, it more than likely a dirty or bad Idle Air Control Valve.
yes