Quote:
Originally Posted by PeteKz
On rare occasions, I will disagree with Henry. Intake air leaks frequently cause starting and running problems, but the metering plate does not come out of adjustment in normal use. If no one has messed with the metering plate or CO adjustment screw since this problem began, do not try to adjust those yet. Most likely, something else caused the problem.
Follow up questions: As kmcteer asked, was any work done recently that may have caused the problem? Did it happen suddenly or gradually? Have you checked the timing yet? Does the distributor RPM and vacuum advance work?
Check all those, and if you still have a problem, try to adjust the idle speed.
Then check for intake air leaks with a "smoke test."
Tell us what you find.
For your reference: https://cis911primer.com/home.html |
Disagree all you want but a hard backfire (CIS engines are known to do that) can easily move and sometime even bend the metering plate. It was common enough for Porsche to offer a tool just for adjust the metering plate.
It's just a place to start that is easy to check, costs nothing and completely non-invasive.