Year/Make/Model: 2007 Mazdaspeed 3
Mileage: 186000
Location/Alitutude: Houston, TX
Concern: Voltage spiking to 18v intermittently
DTC's: P2503, P2504, U140
Modifications: CS cold intake, CS downpipe, accessport, HPFP
ECU/Tuning Software: Cobb Accessport stage 1+
Tuner:
Is the concern...