Misfire when on boost

[MikeA]

Hi,
I have a missfire when on boost / heavy load, engine runs & sounds fine when off boost or at idle.
I've read a few threads on here that suggests it could be a coil gone, however last time I had a coil go, it caused different symptoms - made it really dog rough at idle, on boost and off boost, petrol smell from exhaust etc and this time I havent got any of those symptoms.

Does it sound like a coil or something else? What else could cause the misfire? Its not caused EML to come on yet despite it doing this for over a week. I havent been able to get it on VagCom yet but hope to asap.

Its Running Revo Stg 2, 4bar fpr, jetex exhause from Cat back and Twister filter.

Any ideas welcome

Mike

 

[Beaker™]

I've had this for over 2 months now. Through trial and error i found it to be a weak (not blown) coil pack. Would only missfire under heavy load and would be fine the rest of the time. Vagcom wouldnt show anything either. Put a new coilpack on cylinder 3 and it cured it.

 

[MikeA]

Coil on 3 was changed 2 months ago so hopefully its one of the others this time.
I will change the other 3 and new set of plugs.

Any recommendations on plugs for Revo Stg 2 or will some standard spec NGK's be ok?

Mike

 

[freddie]

your running stage 2 with no downpipe/sports cat?

 

[Beaker™]

I see quite alot of people running stage 2 without k03s, FMIC, sports CAT etc. Not sure why tbh as stage 2 calls for more boost at top end which without the right mods just aint gunna happen.

 

[freddie]

I see quite alot of people running stage 2 without k03s, FMIC, sports CAT etc. Not sure why tbh as stage 2 calls for more boost at top end which without the right mods just aint gunna happen.

Cant see the point myself i just need downpipe then i'll be going stage 2 roll on march cause it bonus month

 

[ChrisCurzon]

when it comes on boost and you get missfire is it realy bad banging of just slight hesitation have a major problem with mine but did have new coil packs and spark plugs but they are the bolt down ones. so wonder if one is faulty. nothing showing on vag com for cf's though.

 

[Robbie C]

As above, sounds like weak coil or plugs to me

 

[r8byb]

I had this, was plugs dude.

 

[MikeA]

Well the Coil finally let go on Thursday, my local Seat dealer had 1 left in stock so I am about to fit it.

Cant see the point myself i just need downpipe then i'll be going stage 2 roll on march cause it bonus month

The reason is because I picked up an ECU with the Revo Stage 2 on and swapped my standard ECU to the other car (which was being custom mapped)
So my intention is to get the downpipe and FMIC as soon as funds allow.
I am well aware that it will not produce the best power at the moment.

I'm not sure if the previous owner of my car ever had to change the coils (I've had the car for just over 2 years now), but it seems that the increase of boost is causing them to fail as this is the 2nd one to go within 2 months - and i've only had the Revo ECU for 2 months!!

Mike

 

[boltyz]

i have just had the same issue. i had a coil go down completely. replaced it but i am now suffering from a missfire under load. have i been unlucky enough to have two coils fail at the same time. i am going to change the remaining three coils tomorro and see wat happens after that.

 

[boltyz]

ok. i have replaced all my coils now and plugs. still getting a missfrire under full frotel. any ideas folks. im running revo2 and supporting mods. still on k03 turbo.

 

[fourtwofive]

check your lambda. also stage 2 you should be running cooler sparks. i had this problem also it came down to lambda get vagcom on it. it could be many things. or a few little things.