V6 misfire

[220bhp]

My wifes 2.6 cabie has started to have what apears to be a single cylinder missfire,at first it was intermitent,I took it for a thrash on saturday and could not find a problem it ran fine.
On sunday it had developed into a single cylinder missfire and at times it was very down on power. Plugs and air filter where fitted about A 1000ML ago along with the cats and the lamda. Any ideas would be much appreciated so I get some piece,at the moment all I am getting is mone,mone, mone,as you can imagine.

[djh]

if its gone to misfiring all the time now could be the POS packing up.

[220bhp]

THANKS

[fzr phil]

could just be a dodgy lead, genuine replacement set is expensive but pattern ones exist. 2.6 and 2.8 is the same. i had the same issue with my mine, and it sorted it.
phil
(don't think there is a pos on that engine)

[spink]

(don't think there is a pos on that engine)

its bolted to the bulkhead behind the throttle body

[220bhp]

Since the last post I have done the following.

NEW LEADS
COIL PACK
POS
DIFFERENT INJECTORS
CLEARED CODES.
NEW SPARK PLUGS

The car ran better for a while but now it is doing it again. Plus when you start the car from cold it stalls a few times then it will run ok.
I have tried to have the codes read,but with no success,the garage said there was no power to the connector in the fusebox,so they couldnt pull the codes.
I have no idea where to look next, so any addvise would be appreciated.

[andy10v]

If it is a single cylinder missfire and it does it at idle what can you isolate which cylinder it is? Eg unplug each plug in turn until one makes no difference?

[siV6Qcoupe]

Do you know if the misfire happens to a specific cylinder or is the misfire random - happens to any cylinder? If it is random then possibly you are looking at a vacuum leak. You may need to take the black plastic plenum chamber off the throttle and take a look at the rubber seal, there is a trick where you can insert a piece of flat telephone cord under the seal to pad it out to create a better seal against the plenum. A failing fuel pump may also cause random misfiring when the engine is under load.
If a specific cylinder is misfiring and plug, lead, injector and coil have all been replaced then a wiring check should be made at the injector plug and the coil pack plug also consider a compression check to determine if the cylinder is holding pressure.

[220bhp]

Its a random misfire,I will check the vacume pipes,many thanks

[220bhp]

At last the car is running right. It was the fuel filter,I looked at this and decided not to change it as it looked new and was tied down with a couple of cable ties,and like a prat I came to the conclussion it had been replaced.
Moral of the story trust nothing

[Alan King]

Hi, just came across this post. I've been having the same problem. Was it sorted after the fuel filter? I've changed mine and it's still happening!

[Lago Blue]

Hi Sir,

One can send the original poster a message that he's more likely to see by simply writing the "@" symbol directly in front of his screen name and then clicking on the little dialog box that appears, it then auto-morphs into this: 220bhp and perhaps he'll respond.

[Alan King]

220 bhp hi, how is your car running? I'm having the same problem. Ive changed all of the same parts apart from the pos, (not sure what that is!). And still randomly dropping the middle coil in the pack. It's absolutely killing me!

[newsh]

220 bhp hi, how is your car running? I'm having the same problem. Ive changed all of the same parts apart from the pos, (not sure what that is!). And still randomly dropping the middle coil in the pack. It's absolutely killing me!

The POS is the power output stage which drives the coilpacks.

[Lago Blue]

If you still looking for the POS, (a great item for your on-board spares kit) it is bolted to the firewall approx. behind your throttle-body. If you can't find one at the wreckers cheap, before you spring for a new one, you may want to confirm that simply the wiring (conveniently under the intake manifold) between the POS and the coil-pack has not had its' insulation abraded and / or oil-soaked degraded to the point it's function is intermittent.

Audi 12v POS photo.png