20v runs rough under accelaration

[solway]

Hi all, my '04 FR 1.8 20VT has started misfiring/running rough when you dump the accelerator, particularly when overtaking (initially the engine management light was flashing when this happened, but is now illuminated all the time). It runs smoothly the rest of the time; it feels like maybe it's overfuelling under acceleration? It's not down on power - if I ease the accelerator down, it still pulls smoothly. Any clues? It's totally standard and has done 110 k miles, but has been regularly serviced. I changed the fuel filter the other day, which hasn't really helped any.

 

[useyourname]

Hi all, my '04 FR 1.8 20VT has started misfiring/running rough when you dump the accelerator, particularly when overtaking (initially the engine management light was flashing when this happened, but is now illuminated all the time). It runs smoothly the rest of the time; it feels like maybe it's overfuelling under acceleration? It's not down on power - if I ease the accelerator down, it still pulls smoothly. Any clues? It's totally standard and has done 110 k miles, but has been regularly serviced. I changed the fuel filter the other day, which hasn't really helped any.

I'm guessing a coil pack has gone. Had a similar issue where when I gave it the beans it gave me a yellow light and a cough. I got a used set of 4 off ebay for £60 and sorted the problem. Of course it could be something completely different... but just my 2pence worth.

 

[mty12345]

Hi all, my '04 FR 1.8 20VT has started misfiring/running rough when you dump the accelerator, particularly when overtaking (initially the engine management light was flashing when this happened, but is now illuminated all the time). It runs smoothly the rest of the time; it feels like maybe it's overfuelling under acceleration? It's not down on power - if I ease the accelerator down, it still pulls smoothly. Any clues? It's totally standard and has done 110 k miles, but has been regularly serviced. I changed the fuel filter the other day, which hasn't really helped any.

Get the fault codes read and it will tell you mate. Probably the coil packs as said, but could be anything really/

 

[Bigjohn84]

I was gonna say coil pack 10min ago

 

[solway]

Thanks guys - will try coil packs.....two have died already in the past 18 months or so. When they failed it just went down to 3 cylinders and had no power. Maybe this is one of the two original coil packs just getting a bit weaker!

 

[Alexis27]

Yeah when one goes the others are sure to follow!

 

[ibizacupra]

coil packs, lean fueling (weak pump) all likely suspects

 

[solway]

Guys, your advice was spot on - replaced the remaining two original coil packs today and it's running smooth again! Just need to find a way to get the engine management light to go off now

 

[Tessitura]

android phone and a ODB bluetooth thing off ebay.

 

[Bigjohn84]

That's good, try disconeting the battery over night or for 30min see if that turns it off

 

[mty12345]

It will probably clear itself after X amount of miles without a misfire

 

[Alexis27]

£12 code reader off eBay. Every VAG owner should have one!

 

[Bigjohn84]

£12 code reader off eBay. Every VAG owner should have one!

Got one and there not that great, OK for turning airbag light of when changing sensors

 

[solway]

Thanks all - appreciate your help