Yesterday while driving home from work my car lost all power!

Boost is set at 14psi 155kW (safe tune)(had a cel need to delete for tgv's) after I have placed a complete ej207(vf30) into my wrx. I have a apexi power ram, gfb mbc, walbro fp. (tuned @ 155kW) for now.

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During the day I noticed a little hesitation in the lower rpm's, (maybe the limp mode as of the TGV CEL)

But on my way home I lost all power in my engine, my lights didn't go off gauges etc still had power, but not in the engine.

I had just enough power to move off the road into a carpark.
I then checked all the hoses no leaks etc, Fuel pump primes with ignition. But then once the key is turned the engine will shake and rumble sounding like it's going to die, so I turn off the engine straight away.

Now this morning (after being towed home) I checked the engine after leaving the battery disconnected for a few hours. Tried to start it.. FP primed, engine started seemed sweet (normal) for 4 seconds and then I heard a squeak or short squeal from the front followed by the engine hesitation and so I quickly turned the car off again.

Any ideas? a belt or somthing? Battery is fine reads 12.3v, all fresh oil & clean coolant. All help would be appreciated