van barks and bucks at speed occasionally
can surely feel it in steering wheel, floor boards and dash
last trip from louisville, ky to cincinnati, oh was a hundred miles of barking 3 weeks ago
has done it a cpl times around town last week
while in cincy I put 10 gal 93 octane in tank and no barking on way back home
humbly appreciate any thoughts concerning this

 

How long since the spark plugs were changed?

 

4 years
I have new plug wires to put on also
do ya think plugs are my problem?

 

Go after the simple things first.

 

old plugs were gapped at .045 and more-supposed to be .035
no bark or buck so far