Slight misfire on B5 RS4

[TopBear]

I picked up my 51 plate RS4 a couple of weeks ago now, and have been getting used to this beastie, which has alledgedly been chipped to 420bhp.

My concern is that there is what seems like a very slight misfire\hunting from the engine, only noticeable at idle, and wondered if this is normal for a 'modded' engine, or is perhaps problems with some of the engine management system?

TIA fellas

[Nige_RS4]

Definately not normal, even for a modded car! When were the plugs last replaced? Have you had it checked over by a specialist for boost leaks, MAF or BPV failures? Do you know who has chipped it?

[TopBear]

Don't know when the plugs were last done, as the car is on 65K miles, would they be part of the big 40K mile service normally?

Im booked in at Star Performance at the end of the month for them to give it a check over and see what's needing doing. I believe it was chipped by the first owner, but unfortunately I dont know where or when that was.

[Nige_RS4]

Plugs should be replaced every 20k miles on an RS4 (not sure what the hand book says)

[quattrosteph]

When i buy a car even in a very good condition, i always do a service on it Whenever the service is due: Filters, oil, plugs...If you can do it yourself it doesn't cost you a fortune and you know it is done.
Have it checked by a specialist if you have some problems and while it is on the ramp have a good look under the car to detect any start of corrosion on some parts

[TopBear]

Are there any technical docs or how do tackle the oil/filter and plugs change on the RS4.

In fact is there any manuals either online/downloadable or in print on maintenance for the B5 RS4?

Cheers guys

[TopBear]

Had the car checked out yesteday at Star Performance up here in Scotland, and the car has a slight misfire in 3 cyclinders, as well as a faulty MAF meter, (same thing as a MAF sensor I presume).

Got them to replace the MAF there and then, and the car now feels a bit more perkier lower down, and I'm getting them to replace the spark plugs and air filter in a fortnight. I'm sure they said that the RS4 takes platinum plugs, but this seems to be contested on other websites? Does anyone on here have view?

Turns out that the car is putting out 381bhp according to the rolling road diagnostic, and hasnt been chipped as the boost is standard.

Other things needing done is alternator belt is noisy, and needs replaced, and its needing discs and pads all round

[Ruical]

Had the car checked out yesteday at Star Performance

Mines just had a few 'Tweaks' done, by Jim and the boys

What a great drive home

Can't thank them enough for the excellent quality of work, knowledge and service provided

Cheers,

Andy

[TopBear]

Had the car checked out yesteday at Star Performance

Mines just had a few 'Tweaks' done, by Jim and the boys

Was your's the Avus silver B5 RS4 with sunroof? .. If so, very nice car mate

[Doug_S2]

A hunting on idle and misfire could be a leak - and if it is a leak you will run lower boost. Misifres and requested boost can be seen with the diagnostic SW. Some RS4s have had bad coilpacks and/or amplifiers. Use genuine pfr7q plugs or bosch f5dpor on higher power ones.

[TopBear]

Got my car back today after getting the big 'belts' service done as well as rear pads, fronts to get done in a few weeks.
But it's still not idling properly, so Jim's suggested fitting another MAF to eliminate the possibility of a faulty replacement MAF. Next after that is to change coil packs, but i might have a go at swapping a good\bad cyclinder pack around to see if the pack is faulty or the something else.

How hard is it to access\change a coil pack, and is there any (clear) instructions on how to do it.

Cheers

[Golich]

Got my car back today after getting the big 'belts' service done as well as rear pads, fronts to get done in a few weeks.
But it's still not idling properly, so Jim's suggested fitting another MAF to eliminate the possibility of a faulty replacement MAF. Next after that is to change coil packs, but i might have a go at swapping a good\bad cyclinder pack around to see if the pack is faulty or the something else.

How hard is it to access\change a coil pack, and is there any (clear) instructions on how to do it.

Cheers

Are you still struggling with this? Its pretty straight forward to remove the coil packs/plugs etc. I have some pics I can email you if you really need. But if you are reasonably 'handy' you'll manage it no probs.

[TopBear]

Got my car back today after getting the big 'belts' service done as well as rear pads, fronts to get done in a few weeks.
But it's still not idling properly, so Jim's suggested fitting another MAF to eliminate the possibility of a faulty replacement MAF. Next after that is to change coil packs, but i might have a go at swapping a good\bad cyclinder pack around to see if the pack is faulty or the something else.

How hard is it to access\change a coil pack, and is there any (clear) instructions on how to do it.

Cheers

Are you still struggling with this? Its pretty straight forward to remove the coil packs/plugs etc. I have some pics I can email you if you really need. But if you are reasonably 'handy' you'll manage it no probs.

Yep, I still have the missfire, so any tips\guidance would be greatly appreciated.
Cheers

[Golich]

PM me with your email and I'll forward pics. All should be revealed. As you say a starting point is to not with VAGCOM which cylinder is reporting a missfire and simply move the coil packs around. If that doesn't reveal anything swap the plugs of the offending cylinder.

[Philws4]

Not had any personel experiance with this but my brother in law (who is a trained mechanic) puts his money on a faulty coil pack.