Starting Woes...

[A4B518T]

So 8 weeks ago I bought my 2001 A4 1.8T, 210 000kms / 130 000 miles.

3 weeks in she started coughing and spluttering a bit but that went away. I took a drive down to the coast and parked for the day, the afternoon when I wanted to drive home she just wouldn't start! Hehehe, so I got drunk and stayed the night. Next morning she started fine! Two weeks later the same thing happened, bit of cough and splutter and then then she died in the middle of the road. I left her overnight and bingo, the next morning no problems?!? So I replaced the fuel filter (was clogged up a bit) and also the fuel pump (made strange noises) oh yes I also replaced the spark plugs just for the hell of it. She ran well for three days surviving another trip down to the coast at 180km/h... and back again! Sorted! until yesterday... got in my car after work and yup, you guessed she didn't start. I removed the access panel to the tank and removed the fuel lines and turned the ignition briefly to check for fuel, nothing. Then I tested for power at the connector, 4.5v with ignition on (Hmmm that's wrong). Took my work vehicle home and this morning when I got in I tried again and Bingo again, she started first swing!

Haven't tested for voltage yet but since I can hear the fuel pump spinning it's gotta be getting the full 12v.

So my question... any ideas? I have a idea but I dunno where the fuel pump relay sits.