A319 Captain reports rejecting a takeoff below 70 knots for low engine power. A Class 2 maintenance message for Eng 1 FADEC had been written up previously but deferred by maintenance.

Narrative

We were using Flex power and the Flex temp was 62C with an outside temp of 23C; Flaps 1+F; APU off. Aircraft began takeoff and the number 1 engine failed to produce the proper power. It was the First Officer's leg. I transferred control to the First Officer when cleared for takeoff. The First Officer pushed the thrust levers up to stabilize the engines at 1.05 EPR and then pushed them up to the climb detent and noticed the number 1 engine failed to spool up. He made the statement 'the number 1 engine isn't producing power'. There was a significant split in the EPR indications from Engine 1 & 2. Engine 1 was 1.5 EPR and Engine 2 was above 3.00 EPR. I immediately called 'Reject; my aircraft' and the First Officer notified the Tower. Our reject speed was less than 70 KIAS. The autobrakes never engaged. We pulled onto the taxiway and I stopped the aircraft; notified the flight attendants and made a passenger announcement concerning the indications and the reason for the rejected takeoff (RTO). I then called Maintenance and notified them of the RTO which required us to return to the gate. The aircraft was grounded and we were given another aircraft. We departed about an hour and half later. First Officer did a good job recognizing it quickly and stating the issue. I have no reason for the cause of Engine 1 not producing the proper power; however; I had written this aircraft up in five consecutive log pages for various maintenance issues; including this one; on two separate days. One maintenance issue had been for Eng. 1 FADEC. It was a Class 2 maintenance message that I wrote up. During this flight with the RTO; I saw that the Class 2 FADEC maintenance message had been deferred and put on MEL. There appeared no reason for the engine not to spool up to Flex power.