Don't look for other faults (immobilizer)yet,did you fit a new rotor arm when you put a new cap on,you should have as both parts burn out together,also did you fit cap on correctly it is easy to have it 180degres out,you can mess on for hours,I would have changed cap,rotor arm and leads and made sure the firing order was right,forget the immob for now if you are getting a spark I doubt it's that, I would think you wouldn't get a spark at all if it was on/dodgy,back to basics.
Rich, February 2010