Yes once I get the truck back from the shop I will perform all the tests you are suggesting.
I will verify where timing is for a second time with vacuum advance connected at 2500 where the missing occurs.
Then I’ll plug the vacuum advance and verify that the missfiring is gone when the vacuum is capped off.
Then I’ll bring distributor timing only up to the same amount of timing when vacuum advance is connected and it’s missfiring and bring rpms up and see if it misses without vacuum advance but at the same timing setting at 2500.
Then I’ll turn the distributor down and plug vacuum advance back inn to get the timing around 32-33 degrees where it is without vacuum advance at 2500.
I’ll report back what I find.
My truck is at the shop waiting to get the front axle grated to 4.56s to match the rear axle.
It is near by but with over a foot of snow on the ground I don’t want to try and drive it with no 4wd, not to mention I don’t have a shop or garage at the moment.
I am moving into a new house at the beginning of January that does have a small garage.
So I’ll be able to mess around with it and not be out in the elements.
I’ve got a lot going on in the next week, we’re moving on the 29th and 30th of the month.
I’m starting a new job on January 2nd.
Just had to get Christmas out of the way with the wife and 3 kids.
And the truck is in the shop waiting to be re-geared up front.
And I still have to figure out this strange missfiring bull crap.
So it’s been pretty stressful to say the least.
Plus I had to give notice to my current job which I do like a lot but this new job opportunity pays 3 dollars more an hour with better benefits and paid holidays and more paid vacation.
So it’s just been a hectic month and I really haven’t had much time to mess with the truck and specially now since it’s sitting at a shop without 4wd.