Hi Carla, and welcome to the forum.
OK, some questions:
When you first broke down - who was it who recovered you to the dealer? And did they plug in any kind of 'tablet computer' into a socket under the dash just above where your right knee would be when driving?
If they did plug in this computer thingy, they should have read the cars onboard electronic control units (ECUs) for any stored "Fault Codes". Each individual cylinder (the GTI has four) will have its own unique fault code - so for example, if ignition coil number 3 was to fail, it would display a fault code directing the mechanic/technician to the exact item.
Then when the second coil failed the following week, again, a fault code will be stored.
Now, if the RAC / AA / Green Flag or whoever plugged in their computer - they normally tell the owner of the fault code. However, whenever any work is carried out at the VW dealer, they should also use their own official fault code reader, before carrying out any work. The dealers very rarely offer this kind of detailed info to the customer though. But you can ask for it.
Staying with these "fault codes" - as I mentioned, when anything 'goes wrong' - a fault code is generated and stored in the ECU. Sometimes, the engine warning light in the dash pannel will be illuminated, for some faults, no warning lights may come on, but a fault code is still stored. Got that? OK, whenever a dealer (or other workshop or brakedown service) carries out work to rectify the fault - in your case renew the ignition coil - they are then supposed to 'erase' or clear the stored fault code from the memory of the ECU. 99% of the time, they usually do - but sometimes they forget to clear these codes. If they happen to forget to clear these codes, then sometimes you can get a warning light on again, and it 'tricks' the car into thinking there is still a fault - and maybe this could be the issue you experienced.
Regarding the engine warning light in the dash - if this lights up, and stays lit whilst the engine is running - then this usually indcates that a fault requires the engine to go into "Limp Home Mode". This limp home mode is basically a way of preventing serious damage to the engine - and usually allows the engine to still operate - but at very restricted revs, and with very little power - usually limited to no more than 3,000 rpm. But this limp home mode should never completely turn off the engine.
Now, regarding the actual coils - on older VWs and Audis - upto about 2002 cars, these where known to cause problems, and it was widely reported on Watchdog of the problems VW had in supplying new ones. But this is long ago - the Mk5 Golf, along with all modern VWs/Audis, don't appear to have any known problems with the ignition coils. OK, so you have experienced failures - but I reckon this is a very, very isolated incident - and is certainly not typical of the GTI. It is reassuring that the dealer has agreed to replace all four coils - and perhaps if you havn't collected the car yet, you might ask the dealer for a copy of their stored fault codes.
Hope all this helps.
