MirekEhrlich

Hello from Czech Republic, I am here with a problem with 1.8 TSI CDAA engine. Car is 2011 Seat Leon FR, but it's not important, engine is the same in many other models. Here is my story with this engine. I bought the car last year in Germany with some light knocking coming from the engine. We brought it home and immediately started investigating what is the problem. After removing head, we found it. Cyl 3 was weirdly melted. Wrong coil, plug or injector? Who know... Cylinder wall was okay, some light scratches but you can't feel them with nail. I bought ONE new piston in STD size (measured bore/old piston, STD is correct size) and installed it. I also installed new timing chains, guides, tensioners, NGK coils and plugs, injectors cleaned and tested with no problems (that's weird, because we thought injector 3 will be faulty, but it was okay...). When assembling head I found that variable timing gear on intake cam has some play. I discussed it with some friends who had hands on cams from TSI engines and they never had a play in it, so I bought new OE camshaft. New cam had obviously no play in gear, so after that I assembled it. Car started fine, runs very well. After a few months of driving, I found another problem. Oil consumption. 2 - 2.5L/1000km. So I started to buying parts for rebuild. New pistons, gaskets, PCV valve, another new plugs etc. Basically everything you need. One day I started to disassembling the engine and pulling pinston nr. 1, 2 and 4. 3rd pistons was okay, since was replaced with revised one and Cyl 3 has no problem with oil consumption (spark plug was brown, no signs of consuming oil). With new pistons I also installed new valve stem seals and cleaned all valves (intake had some carbon build up). Assembled the engine, started it, runs very well until first drive... And here it beginning. All 4 cylinders randomly misfiring. But only between ~1000 to 2500 rpms. No matter if it's cold or hot. After passing 2.5k rpms, misfiring is gone and engine pull hard to revlimiter with zero misfire (logged with Delphi diagnostic). So, I bought another pile of parts and started replacing. New OE plugs and coils, Facet cam and crank position sensor, Delphi knock sensor, INA timing control valve (it's bolted inside intake cam) and INA control solenoid. No change. It was pointless to replacing all these parts, but car is not throwing any codes and I was out of ideas. After that I also checked timing. Removed all chains and guides and set it again. No change. Timing was okay of course. I have no idea what is that. So that why I am here. Is here someone with some ideas what could be wrong or what I should check next? Also sorry if I made some mistakes in text. I learned English 10 years back. Thanks for help!