I seem to recall a few people having problems with random multiple misfires on a specific cylinder and not being able to solve it despite replacing or trying several things. The VCDS scan showed up codes: 000769- misfire detected and a specific cylinder number and
000768- random multiple misfires detected.
There was also a fuel supply fault code which I can't find right now that pointed to the cam. Things to look at included coil packs either vw recall or upgraded, sparkplugs, and cam follower off the top of my head.
The problem with my car wasn't a constant and would only become noticeable on boost when you're pressing on. Normal day to day driving and general running about you'd never know there was a problem.
I'd had my coil pack recall done earlier by VW and hadn't had a problem. Shortly after having the car serviced though and the misfire began. A couple of return visits to try and fix things (coil packs checked, new spark plugs replaced and cam follower checked and checked again) would seem to improve the situation but very quickly the misfire would return. Situations and circumstances dictated a fair amount of time passing and losing confidence in my garage I began thinking about the injectors themselves and sorting a new company to look after my car.
Consensus seems to think they're pretty much the last call and very rarely cause problems down to the direct injection setup. Anyway I found a complete set including loom from a low 46k mileage gti on ebay for a ridiculously cheap price and had them sent to Injectortune who have there own ebay page. There's a nice write up and little video to watch what your injectors will go through and lots of happy customers feedback. They provide a written report on the injectors, flow patterns, volumes pumped before and after and replace parts where necessary etc etc and off they went for service. 2 days later they're back by special delivery pristine and ready to go. The report showed that the spray pattern was good to fair on 2 injectors and good on the other 2. Volume of fluid able to be pumped through was also down across all 4 injectors although they were all roughly similar. They came back all spray patterns corrected and improved with the amount of fluid being pumped through back to as new levels.
Following guides on here and other sites I intended to do the replacement myself, all seemed pretty straight forward. However with about three steps to go and due to slight differences with the fuel pump and fuel lines from the posted guides I ground to a halt. Retraced my steps putting everything back together and taking to a new garage that I'd started to use. I told the garage the problems I'd been having and what I'd already looked at and they cracked on with job.
Picked up the car the next day and they'd done a diagnostic on the car and stated all clear!
Excellent news and going for a very long drive down to Christchurch to give the car a good test everything was back to normal. In fact better than before as the throttle response has improved, obviously no misfire so acceleration was rapid and on top of all that mpg was considerably improved.
Unfortunately I didn't take any pictures of the ebay injectors but when you see the pictures of the one's that came out of my car I could probably have done a straight swap as the difference was night and day. However that would have defeated the object of finally trying to get the misfire sorted by tracking down what the actual cause was. Also bare in mind these injectors have done 153k miles, the majority of which is motorway commuting so no harmful short distance stop starting but still a bit of a shock.
These are what came out...
So as you can see 2 of the injectors look a lot worse that the other 2 and one in particular (the last pic) was the one causing all the issues in cylinder 1. I'd really like to get these sent off to injectortune for a comparison; a to see how bad they really are and b to see how they compare to the ones bought off ebay.
As a service I can't fault Injectortune, combined with the write up and condition of the parts returned and for £57 I think thats pretty impressive. I can't remember what the cost is of a single injector from VW...i think around £98 but most importantly it has fixed the misfire which was plaguing my car.
Ps before I forget the garage in bristol has been "recommended" by a couple of people but after my findings I won't be going back. In an attempted earlier fix, they injected high temperature grease into a coilpack to increase the electrical connection with the spark plug??? WTF!!
I am now very happy with the new garage that I have found and after a couple of routine visits they'll continue to look after my car. Also very refreshing to see an indy garage that is full up with nothing but that make of car in the carpark and on the ramps.
