water in the fuel can cause an idling motor to sputter and/or die.
Dirty fuel injectors.
that depends on size of engine
The fuel pressure regulator maintains a constant predetermined fuel pressure regardless of engine RPMs.
Check fuel pump pressure Should be 15-23 with engine idling 23-31 key on engine off
Change your fuel and air filters.
4.7 liter per/hour
set the idle down on the carb
check fuel to engine from fuel pump.or a clogged up fuel filter.
Yupp Clogged fuel filter. Hole in the gas line.
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.
Lower emissions Better cold engine starting/idling better fuel economy and in most cases more power through out the powerband.