loping, missing, and popping
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
Is it possible that one or more of the plug wires is bad? Have you checked inside the distributor cap for signs of arcing? If all that is good, sounds like time for compression test of all cylinders.
Moderator
Joined: Dec 2007
Posts: 7,987
Likes: 104
From: Boise, Idaho
Vacuum Gauge Test - YouTube
On the youtube video, skip to around 1:10 or so.
Some other sources:
Intake Manifold Vacuum Tests
How to Use and Interpret a Vacuum Gauge
I'd definitely check to see if your cap and rotor are good, sparkplug wires are in good condition, and you don't have any worn or cracked sparkplugs.
On the youtube video, skip to around 1:10 or so.
Some other sources:
Intake Manifold Vacuum Tests
How to Use and Interpret a Vacuum Gauge
I'd definitely check to see if your cap and rotor are good, sparkplug wires are in good condition, and you don't have any worn or cracked sparkplugs.
Post Fiend
Joined: Dec 2007
Posts: 8,521
Likes: 16
From: Lost
Broken rocker arm or valve spring can cause this, as can a flat cam lobe. Just a few more things to ponder.....
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Postmaster
Joined: Mar 2005
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From: Earth
Warm it up, put a can of Marvel's Mystery Oil in the crankcase, let it idle for 15 minutes and change the oil. As far as Band-Aids go it's decent stuff. Napa sells an engine flush in an old school one quart metal oil can that works pretty well too.
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