Great. Thanks guys. It had been a while since I did a Sea Foam treatment.
Aussie - my idle temp has definitely gone down. Just seemed to make everything run better by going directly to manifold vac for the spark.
The way the TVS was plumbed, at ‘normal’ engine coolant temps the vac advance was controlled by ported vacuum. Elevated temps would switch to manifold vacuum. The days I had my stumbles were very warm. The day I got stuck was extremely hot and I was cruising at 70 up a long grade. I’d guess that engine coolant temps were elevated. If the TVS tried to switch the spark to manifold vac and for whatever reason got stuck and eliminated vacuum to the can, could the loss of 15* of cruise timing cause the stumble and surge?
If I sound at all frustrated, I’m not. This stuff is fun.
