I am having the exact same problem as well. Went to the ignition guys and they couldnt find thew problem. I am gonna give that valve a try. Mine usually happens when I accellerate/back off and accellerate around 80KM/hr. Its annoying as hell when you are jockying in traffic.

THnks for the IDEA. I will hunt down a replacement valve or get my garage to do it.

96 Contour 2L Zetech no mods (i'm boring) vomit purple, I mean desert violet (Now who would want to steal something that ugly)