Hi there, I now live in the UK and about 2 weeks ago I privately purchased a 2004 Audi A3 3.2 Quattro DSG with 90k miles on the clock. I took the car for a test drive before purchase and it ran very well, was also in very good original condition. It was delivered to me on a transporter and parked around the back as I had no other way to collect it. Later that day I took it out for a run and within minutes it started misfiring very badly under load but would idle OK. I got the RAC to look at it and they said the ECU was reporting multiple misfires on all 6 cylinders and that a garage would need to look at it. They also advised that it was strange that the engine light was not on. I got the car transported to the nearest garage they recommended which was in Ealing. After looking at it they advised that 2 pencil coils were faulty and recommended replacing them all which was done. 500.00 pounds later I collected the car and the problem was gone although I did notice a small miss when idling which was very slight and more like a small flutter than a solid miss but it did show up as a flat spot between idle and about 1200RPM when taking off. Also when idling if you very lightly increase the engine speed between idle and 1200RPM the engine will die off and start hunting a bit and once you get above 1200RPM it will rev off and is fine. Firstly it seems very strange that it drove OK a couple of days before on my test drive as I would have definitely noticed the missing problem as it was very bad and almost seemed to be misfiring on all cylinders and not just two. It is also strange how these two coils could have failed in just a few days and on the back of a transporter, also that the ECU showed the problem on all 6 cylinders, which is what it felt like, but the engine light was not on?
On that weekend the next day after collecting it we shifted from Ealing, London to High Wycombe and drove the car to and from London and High Wycombe several times and around High Wycombe without a problem apart from the idle miss and flat spot up to 1200RPM. However on the Monday night the engine light came on but apart from that it ran fine until the Friday morning where after driving about 5 minutes into work the car started missing again very badly lake before except it was now at the lower revs up to about 2000RPM and would not idle at all unless you worked the accelerator to keep it running. Again it seemed like it was misfiring randomly on all cylinders and whilst it could be an ignition fault it seemed more like it was starving for fuel as when you worked the accelerator you could get it to pick up and run a bit all be it very roughly and totally un-drivable. Also it would run over 2000RPM plus all 6 pencil coils had just been replaced. I arranged to take it down to a local VW/Audi garage and when I got into the car it started and drive down there fine with no sign of the problem apart from the low speed/take off flat spot. The garage checked the ECU and advised that it had misfiring listed on 3 cylinders and told me I needed to change the 6 pencil coils, which I had told them had been changed just the week before. They told me I should take it back to for first garage otherwise I would need to pay them another 400-500 pounds to get the coils changed again, which is not easy now I live and work in High Wycombe and the other garage is in Ealing London. I drove the car from the garage back to work a couple of minutes down the road and it was fine but on the way home a couple of hours later I stopped to get fuel and the problem started again at the service station. I managed to get the fuel and get the car off the forecourt to the side where I sat starting and stopping it for about 20 minutes. It would start fine every time and after a few minutes or less it would start misfiring badly but interestingly the more time went by the longer it would run for each time until it got to the point where it was fine again and I could drive it home without a problem apart from the idle and flat spot. I Haven’t tried it again since then but will do when I get a chance when it had stopped raining here. I will obviously need to get someone to look at it but was looking for some guidance on what may be wrong as I do not know anyone here that I have experience with to look at it and do not have much faith in a lot of garages and dealers as I have heard a lot of horror stories and experienced a few problems before with garages and dealers who really don’t know what they are doing and just keep replacing parts until they find the problem and then hand you a huge bill as this is the only way they know how to fix things. I have done quite a lot of mechanical work myself with rebuilding engines and gearboxes etc but that was on simple carburettor type engines and nothing like this 3.2 V6 but I do at least have a few clues know that the garage’s idea of replacing all 6 pencil coils in less than 10 days is maybe not where the problem lies? With my limited knowledge it now seems more like a fueling problem where there is an issue with the sensors or ECU and it is not operating the fuel injection properly starving the engine. It also seems like there are two problems being the idling/flat spot and the bad missing problem but strange that none of them were present when I test drove it a few days earlier? I also wonder if there could be a problem with the fuel getting low as the fuel light was on when it was delivered and had the original under lead missing problem and the fuel light went on, on the Friday morning when it started missing again but then it ran OK later that day to the garage to be looked at and the fuel was still low. The fuel was also low when I drove it from the first garage who changed the pencil coils until I got to a service station and it ran fine then also.
Sorry this is so long but I thought it best to explain everything as best I could and hopefully someone there can give me some pointers as this could cost me a fortune if I am not very careful or lucky. Would also be good to get some good pointers for service people in my area if anyone there can help? I look forward to hearing back, cheers, Gavin