3.0 v6 sport running rough again

[A4B6Cab]

My Audi is running a little rough, but only when accelerating between 1500-2500rpm. Was serviced less than 1k miles ago, new oil and filter, air filter, plugs, rocker cover gaskets. Been missing on low revs for the last 3 or 4 weeks. Have scanned it and no codes present.

was running lumpy a few months ago, and I ended up replacing all 6 coil packs. That was running rough constantly but this is just when accelerating on low(ish) revs

ive run some injector cleaner through just in case. Car has done 130k miles

any ideas please guys?

[Crasher]

I have known none genuine coil packs fail very quickly, what did you fit?

[A4B6Cab]

Hi Crasher

they were just cheap Starline ones from ECP. Funny you say that I had to get one replaced as one of the new ones failed after about 3 weeks. Picked it up on a scan.

this kind of misfire is only at low revs when accelerating, not when idling or driving normally. Plus wouldn’t another duff coil pack show up on a scan? No engine faults came up when I scanned it recently?

[Crasher]

I won’t touch that crap, Bosch or genuine.

[A4B6Cab]

Starting to wish I’d done the same Crasher. But wouldn’t another failed coil pack show up in a scan? I was getting ‘misfire cylinder 2’ until I replaced the duff one. It’s running better, not missing all the time, just at low revs when you accelerate, there’s hesitation and a slight delay. Not quite a ‘cough’, but it’s there

any other ideas?

[Crasher]

I forgot to ask what the pugs are and how old? With suspect brand coil packs, in this situation I tell a customer that I must know the plugs and coil packs are perfect and go from there BUT unfortunately no guarantee of success as otherwise I could spend countless hours at £72 an hour chasing the fault only to come to the initial conclusion.

[A4B6Cab]

Sorry Crasher I should of said, they are NGK (BKR6EKUB) from EuroCarParts

[mickeybo]

This problem covers a multitude is there any time this happens either hot or cold can you post post up engine code. It would not go amiss to check out engine coolant temp sensor & fuel temp sensor if your drives ok after 2500 rpm then i cannot see this a coil problem

[A4B6Cab]

Thanks mickeybo. Had an engine light come on yesterday and got these 2 codes:

p0421 warm up catalyst efficiency below threshold bank 1
p0431 warm up catalyst efficiency below threshold bank 2

am guessing either the cats themselves, or the oxygen sensors after the cats? Any easy way to pinpoint the issue?

and I don’t live anywhere near an Audi main dealer, so where would you order oxygen sensors from if needed?

[Crasher]

I have had a number of these where the primary cat has disintegrated usually due to driving with a misfire for too long.