[V8] V8 rough running - Still

[Greg]

Ok all.
This continues from "v8 problems go om - ignition running rough"

I'm looking for more ideas. The 91 V8 I have still has an attitude! 
 After new caps and plug it still runs rough. When I pulled the old 
plugs  #1 and #3 seemed fouled (black) - and yes they are on different 
 caps. Anyway, after the replacement of the caps and plugs it seemed to 
run a bit smoother - for 5 miles or so then started acting up again. 
Between 2-3K rmp it seems to cut out and backfire. YUCK!

Returned home and left the run run at about 1k rpm for about 1/2 hour 
while I tried flashing the codes - none! I pulled the new plugs thinking 
1 & 3 would be bad again this time they looked fine. I was going to 
replace the plug wires but all plugs look good now.

Any thoughts or help - I miss driving the V8 and now winter is here!

Greg