Help needed

[Gatesy]

Need some help with a problem on my FD guys.
Noticed the car wasn\'t running right when returning home last night (mile or so journey) lots of very loud pops and bangs from the exhaust.  
Pulled onto the driveway and when I took her out of gear she was idling very very erratically with the revs dropping to almost stalling point before going back up to about 2000rpm.  My voltage on the apexi said 6volts whereas it normally shows about 14v.
Immediately killed the engine and let her sit for 2 minutes before trying to fire her up.  Started first time but still idling erratically and the volts around 6v.
Now when I turned the engine off and just turned the ignition on the volts were sitting around 5.3-5.4v instead of around 12v.
I checked the battery connections and they are fine and the plugs to the alternator are fine, no belts gone and all hoses still in place.
Left her over night and started her this morning, again around 5v with the ignition on and she started first time and volts go up to about 6v. Had to go to work then so left her home.
Got home tonight and tried again, same thing but loads of blue smoke that smells of pure petrol, used a tester on the battery and its reading at just over 12v so its not that.
I\'ve spoken to my Guru DaveHG and we\'re going to try swapping the alternators over but just wondered if anyone else has had this problem and if theres anything I can try before swapping bits over.
Really hoping its not the engine as just spent my rebuild money on the FTO.

[SmbFD3S]

Hmmm thats wierd yeah !! But if the apexi is reading 5-6v on 2nd position without engine started then i wouldn\'t have thought it would be the alternator as this isn\'t running??  Could be voltage regulator or something like that?? although i\'m guessing tbh.
 
Did you put the test leads on the battery when the car was running or stationary? obv when running it should be reading 13-14v if alternator is charging ok? But that still wouldn\'t explain why the apexi is reading 6v.....

[Gatesy]

Right problems fixed itself though I dont expect it to stay fixed, carrying tools and a multimeter in the car and next time it does it I\'ll start pulling fuses out as I think it may be a dodgy connection somewhere!