Misfiring, uneven idle, slight cutouts on acceleration

[Grid]

I've recently started getting the symptoms as per title. Idle seems a bit unstable - I can feel the engine does not have smooth RPMs but fluctuates slightly, and has the odd cutout/rpm drop (misfire?).

On acceleration it is not smooth either and can feel a similar misfire happening randomly, sometimes including a spot of knock (CEL on knock) or a bang from the exhaust.

Should I be looking at the spark plugs or coils? If spark plugs are fine then is it time for a COP kit?

Car is tuned on brand new 1000cc injectors from TME Steve.

Oh and the misfiring/hesitation is much worse when I switch fuels to LPG. LPG is undriveable right now due to this.

 

[Grid]

 

[Nitephyre]

Plugs, coils or injectors most likely.

 

[naughtika]

how many km's have you travelled with your current spark plugs? I recall when i was still on OE coils, my car sounded like a subaru after a good run and idles erratically.


if they are NGK BKR7EIX's and i you have done at leaset 30k kms on them, I'd be my money on that. If you are using Denso VK's or IK's and you've done similar KM's I think it'll be your coils not being able to provide enough spark causing them to fail prematurely

 

[Grid]

Plugs are Denso IK22's. Sounds like that coils and possibly plugs are the culprits here indeed. From what I heard, weak coils can also contribute to premature spark plug failure...

 

[MatiLP640]

I had simillar thing after tune... Changed plugs from NGK to Denso and everything was gone

 

[steveP]

How old is the fuel pump?

 

[Grid]

Fuel pump is 1 year old, also there is an external fuel reg so that would be all fine. Only element in the fuel-ignition chain that has not been recently changed are the coils. Going to look into it this weekend.

 

[Grid]

Plugs look good I guess, tan on one side, slightly sooty on other. Due to things being pig-rich probably.

 

[naughtika]

clean that up. How you will do this, it's up to you, just be careful with the center electrode.

Also I don't think your coils are providing enough sparks as that whole ground electrode should be white-ish in color not black.