Smaller engines often surge when the AC "cycles". Next time, see if it's surging when the AC compressor turns on.
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.
The first things to check are the air intake, the fuel pump/filter and the governor.
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.
An engine surge at idle in a Pontiac Grand Am can be caused by several factors, including a vacuum leak, a malfunctioning idle air control (IAC) valve, or a dirty throttle body. A vacuum leak can disrupt the air-fuel mixture, causing erratic engine behavior. The IAC valve controls the amount of air entering the engine at idle, and if it's faulty, it may not regulate airflow properly. Cleaning the throttle body and checking for leaks or faulty sensors can help resolve the issue.
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.
auto or stick shift
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
A 2002 S10 may surge at idle speed due to several potential issues, including a vacuum leak, which can disrupt the air-fuel mixture, or a faulty idle air control (IAC) valve that fails to regulate the engine's idle speed properly. Dirty fuel injectors or a clogged air filter can also contribute to inconsistent idle. Additionally, issues with the ignition system, such as worn spark plugs or ignition coils, might cause irregular engine performance. It's advisable to perform a thorough diagnostic check to pinpoint the exact cause.
if surges worse at idle when cold possible intake manifold gaskets leaking will usually set o2 or fuel trim codes