Problems after timing belt change 2003 VW gti 20th ann

[wpuccinelli]

About a week after timing belt change had engine speed sensor fault replaced and ran fine for two weeks then same problem. Car runs and idles fine but will start to stumble about 3500-4500 rpm range.changed cam sensor same problem. Then to add to that EPC light came on and RPM gauge while driving dropped to 0 rmp then jumped back up. Turned car off then back on EPC code gone. My understanding is that if timing belt was off a tooth that car would run like crap correct me if im wrong.And for some reason i noticed that the clock and mileage stays on the display never paid attention to that before shouldn't it turn off when ignition switch and car is locked.I have the Ross Tech VCDS KII-USB It will show fault half the time but no engine light the next day light will turn on.

Thanks for any help im stuck

[nitroscope8]

The engine can be off a tooth or two and you may never notice a running change....or it can run poorly. Check your timing first and go from there. If the timing is SPOT ON then you may have fueling issues such as a failing fuel pump which can cause a timing code. If you have "incorrect allocation" fault, your timing is off.

[Tippman7641]

Especially since you have a BPY engine(FSI) probably a fuel pump cam and follower. What codes do show up when you can read them?