I have a 2003 Golf IV 1.6 FSI (engine code "BAD"). If I accelerate, particularly if going uphill, the engine hesitates/jerks/misfires.

VAG-COM has periodically showed:

17413 - Torque Difference Cylinder 2: Limit Value Exceeded
P1005 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16688 - Cylinder 4: Misfire Detected
P0304 - 35-10 - - - Intermittent

So far I have had replaced: the coil-packs on cylinders 2 and 4, the spark plugs , the fuel filter, the fuel pump (which died apparently by coincidence). Also ran through a couple bottles of injector cleaner at the suggestion of the garage. No difference.

If I delete the errors, they don't come back immediately. But the 17413 and 16688 usually reappear after a few weeks or a couple 100kms. I'm not sure if they will reappear since I had had the coils and plugs changed last week. Readiness fields are all clear.

Still, the engine continues to jerk and apparently misfire consistently, even while no error is recorded. Not enough to make the car un-drivable, but unpleasant.

Two garages (one VW dealer, one local garage) have tried to figure it out, and they're really just guessing. I'm no auto mechanic, but I have VAG-COM, and am happy to do some diag work if I know what to try. Is there something I can measure in the absence of a consistent fault code being produced that would indicate the problem?

Grateful for your theories or suggestions.