beyerku
Junior Member
- Joined
- Jan 4, 2023
- Posts
- 7
- Reaction score
- 8
- Location
- Iowa
- First Name
- Kurt
- Truck Year
- 1975
- Truck Model
- K20
- Engine Size
- 350
1975 Chevy K20 with a 350 crate motor from maybe 20 years ago. Rough idle, huge off-idle stumble, poor brakes, etc. I finally decided to eliminate all of the variables (vaccum leak, timing, etc.) and replaced the spark plugs, vacuum brake booster, and the entire distributor (coil, vacuum advance, etc.) When I first started the truck it ran better than it has since I was a kid. Perfect steady idle, absolutely no off-idle stumble, etc. I turned the idle to about 850 which is what I was used to.
Drove it a week until today. Went to work - ran perfect. Left work 90 minutes later - runs like crap, exactly like it did right before I worked on it. Idle dropped to 600, massive off-idle stumble. It’s like everything I fixed just magically unfixed itself. I pulled the vacuum line off the new booster and plugged it and it still ran poorly, so I don’t think the booster is bad. What the heck happened? No vaccum lines are damaged, and nothing has changed? I am flabbergasted. Help!
Drove it a week until today. Went to work - ran perfect. Left work 90 minutes later - runs like crap, exactly like it did right before I worked on it. Idle dropped to 600, massive off-idle stumble. It’s like everything I fixed just magically unfixed itself. I pulled the vacuum line off the new booster and plugged it and it still ran poorly, so I don’t think the booster is bad. What the heck happened? No vaccum lines are damaged, and nothing has changed? I am flabbergasted. Help!
