Intermittent erratic idling and hesitant acceleration

[Kklim]

Got a 2009 Sylphy 1.5 (non-CVT). Been having intermittent erratic idling when stationary and engine hesitation when accelerating; CEL light didn't come on. Spark plugs and air filter are newish and I clean the MAF sensor with CRC cleaner regularly. Brought to workshop (ex-Tan Chong staff) for checking but no fault codes surfaced. Swapped MAF sensor, filter, PCV valve but couldn't pinpoint the problem. What else could it be? Clogged injectors, faulty crankcase positioning sensor? Thanks for any help.

[Adrianli]

Fuel system?

 

Fuel pump, fuel filter and fuel injectors got check?

[RadX]

fuel pump or filter

[3pinplug]

Got a 2009 Sylphy 1.5 (non-CVT). Been having intermittent erratic idling when stationary and engine hesitation when accelerating; CEL light didn't come on. Spark plugs and air filter are newish and I clean the MAF sensor with CRC cleaner regularly. Brought to workshop (ex-Tan Chong staff) for checking but no fault codes surfaced. Swapped MAF sensor, filter, PCV valve but couldn't pinpoint the problem. What else could it be? Clogged injectors, faulty crankcase positioning sensor? Thanks for any help.

 

also check ignition coils.

[Uranium2k]

Potentially ignition coil. I experienced the same thing previously. Changed out all 4 and issue resolved.

[Kengheng450]

O2 sensor lah

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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[Itsec]

mine is ignition coil

[Watwheels]

By right what ppl mentioned here should trigger a fault code. Things related to fuel like fuel injector, fuel pump and fuel filter you should have some trouble starting up the engine (fuel starvation) but you didn't  mention so all these can be ruled out. There should be intermittent stalling too.

 

If ignition coil there should be symptoms like bad fuel consumption stalling, misfiring....should be quite obvious and confirm trigger error code. Same as fuel starvation. If no fuel or unable to ignite starting up is a glaring issue. But yours isn't the case.

 

So comes down to vacuum leak. It will also give the same symptoms you are facing. But how come no fault code? Could be small leaks on the vacuum hoses or gasket (on the throttle body).

Edited February 20, 2017 by Watwheels

[Beng2]

throttle body problem?

[Agalvilaku]

By right what ppl mentioned here should trigger a fault code. Things related to fuel like fuel injector, fuel pump and fuel filter you should have some trouble starting up the engine (fuel starvation) but you didn't  mention so all these can be ruled out. There should be intermittent stalling too.

 

If ignition coil there should be symptoms like bad fuel consumption stalling, misfiring....should be quite obvious and confirm trigger error code. Same as fuel starvation. If no fuel or unable to ignite starting up is a glaring issue. But yours isn't the case.

 

So comes down to vacuum leak. It will also give the same symptoms you are facing. But how come no fault code? Could be small leaks on the vacuum hoses or gasket (on the throttle body).

Mine too had ignition coil issue but no error code when checked. Anyway, mine is Honda City, but, the symptom seems to be ignition coil to me. 

[Uranium2k]

Mine had no error code triggered too. Same symptoms and was eventually narrowed down to faulty ignition coil.

[Kklim]

Thanks, guys.

Did throttle body cleaning and workshop checked for vacuum leaks (none found) but problem came back after a while. EGR and PCV valves also ok. Guess it's ignition coil problem. The stuttering happens open after a drive and when car is stationary.

 

Is the part number 22448-JA00C ? Thinking of getting an OEM set.

Edited February 21, 2017 by Kklim

[Winning]

Previously mine was fuel pump caused ... better check