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sungpil kim

sungpi ... 10/16/2022

2011 Kia Soul ! 4 Cyl 2.00L


Engine Feeling rough

sometimes car feels normal
sometimes car does not feel good
Been driving like this for over a year and check engine light never comes on
Problems seems to come and go
The problems are as follows:
Either engine wants to rush or is slow
Slight drop in mpg
Car makes a hiccup when stepping on brake
The very first moment of pressing gas pedal isnt smooth
Engine feeling slightly louder and rough
Engine Feeling slightly weaker
engine hiccup seems little more noticeable when making right turn
car feels better and improves mpg after filling up gas
Power steering feels stiff once in a while
Previous Mechanic did spark plug, wire, fuel injector, Throttle body
Possible source of problems?

1 Answer


Jimm 10/16/2022

Possible Causes of Engine Hesitation or Stumble:

Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)

Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires


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