Depends what is wrong. A surge can be due to a vacuum leak that allow more air and the computer compensates by adding more fuel. An intake manifold, vacuum line can be the source. I have located these by listening for a wind rushing noise or whistling noise, or by spraying carb cleaner around suspected areas and noticing an idle change.
Most common cause of surging is a dirty/clogged air filter.
A 1994 Cadillac Deville that has an engine surging problem and is stalling out can indicate it is not getting enough fuel. The fuel filter may be clogged.
you press lightly on the brake pedle
Surging is often fixed by replacing the fuel filter. A simple job and most small engine shops will have the part.
first you will need to determine if it is surging due to a fuel issue or governor issue. to do this hold the throttle linkage at the carb from moving. slightly higher than at idle. if it stops surging then it is the governor that needs to be reset. if it continues to surge then you have a fuel issue
It could be as simple as a vacuum leak but without knowing what year, make, model and engine it is hard to tell you what it may be.
Engine surging is usually due to insufficient fuel supply. Probable causes could be an air leak in the fuel system, or possibly a dirty fuel filter, causing fuel restriction.
the water was surging over the rocks
replace the egr valve the one you have is not good
The most common cause of engine surging (rev up and down) is a dirty air filter.
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.
It could be as simple as a vacuum leak but without knowing what year, make, model and engine it is hard to tell you what it may be.