Had a day last week with a Detroit 60 that taught me something new
I was working on this old freight truck from a local dairy, been in the shop before for the usual stuff. Last Tuesday it came in with a weird surging idle, I was about to swap the injectors. Turns out the gear train timing was off by 2 teeth, been like that for probably 100k miles. The old driver said it always ran rough but 'never quit' so they ignored it. Has anyone else found something like that where a simple timing check saved a ton of guesswork?