Ignition Problem

[Simon Quested]

Hi All

I think I have finally tracked down my bad idle problem.....only now 
I have to fix it.....

The engine doesn't want to idle smoothly under 1000rpm
The compression check was good.
The timing is good.
With the timing light connected to the coil lead I could see it 
dropping spark now and then (no pattern)
So I connected works fluke scopemeter up to the -ve of the coil and 
this is what I saw.....
http://www.lincoln.ac.nz/ccb/techs/simon/netpics/coilpuls.jpg

I have a few things connected to the same power source as the 
ignition. have a look at....
http://www.lincoln.ac.nz/ccb/techs/simon/netpics/power.jpg 
I'm pretty sure the problem isn't on the 12v side as the power 
looked smooth and when I put a 12,000mfd 65v capacitor across 
the power it made no difference to the signal or the running of the 
engine. 

Is there any way that I can check the ignition module ?

Cheers

Simon  

My efi unit gets the injector fire signal from the -ve of the coil and 
I'm wondering if the efi unit is causing the problem
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  Simon Quested (E-mail questeds at lincoln.ac.nz)
  Computer Technician, Silicon Graphics & Windows NT Support
  Computing and Educational Resources
  LINCOLN UNIVERSITY OF NEW ZEALAND
  Phone (64)(03) 3252811 Ext. 8087
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http://www.lincoln.ac.nz/ccb/techs/simon/default.htm
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Madness takes its toll. Please have exact change.
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