Audi Repair: 1997 audi cabriolet questions, audi cabriolet, obdii codes

Question
i just bought and am sorting thru issues.  any help greatly appreciated:
1)CEL is on and ABS light - pulling 4 OBDII codes.  a) cyl misfire #2 b) cyl misfire #3 c) cyl misfire random cyls and d) ABS brake module failure or sensor.  replaced plugs, runs better.  lights didnt go away.  injectors?
2) slight brake shudder during braking
3) seatbelts wont retract - dealer quoted $240 each for new belts with retractors!!
4) fuel gauge "wavers"

Answer
That is a number of misfires, sounds like at least one coil pack is bad.  ABS module, check all the fuses and relays, including the one under the black ABS pump cover.  Brake shudder either seized caliper, or warped rotors.  Seat belt retraction problem, I would try exercising the mechanism, perhaps it needs cleaning.  Fuel gauge wavering, does it keep on oscillating, or is it only at a certain fuel level?  Could be a bad fuel tank transducer or a gauge problem.
Let me know how you get on,  Jan