try swapping it out with a known good one before spending your money on one. too many folk needlessly change things without diagnosing the actual fault.

as i was saying on another post, there are 2 channel amps available that are suitable for use with a coilpack. i don't know if you use one of them if it is capable of running with just one channel? i would pm simon (SECS) if i were you, he's the expert on this kind of t'ing