where's the short? '86 5Kcst

[RODNEY MICHAELSON <HOTROD@pacbell.net>]

Need assistance on finding where to look for short.
On my last 1100 mile trip last week-end in the '86 5cst 5speed with
165,000 miles there developed a shorting that caused the engine to miss 
at around 3,000 rpm, the speedo to jump around in the 75-85mph range, and 
the trip computer to either read eradically the boost, miles left reading 
or blank out all together. Stopped for gas and cleaned the three spade 
terminals going to coil. Seemed to help for a short while but then came 
back. Drove last 200 miles home like that. Seemed to happen at around 
80mph and around 3,000 rpm. When I got off the freeway and into town I 
could run any rpm I wanted and trip computer behaved fine.

Next day cleaned contacts at coil again. Drove it around town and no 
problem. Haven't got it back on the freeway yet. 

Any ideas where to look?
thanks,
Rod Michaelson