Intermittent idle problem
Thread Starter
Heel & Toe
Joined: Jun 2011
Posts: 22
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Intermittent idle problem
I need some ideas folks....
My 1979 will idle perfectly when in gear one moment, then suddenly it drops to 300-400 rpm and the car shutters and shakes. At the next stoplight it may or may not do it. It changes from a good idle to shaking and shuddering with no rhyme or reason.
I've rebuilt the carb, no change. I've checked the timing, adjusted the idle mix screws using a vacuum gauge, I've inspected all the vacuum lines. I just can't find anything!
One clue that makes me think it is a vacuum leak, is that when it starts shuttering with a low idle rpm, I can place my hand over the air horn and the idle picks up and smooths out. If I put my hand over it when it's idling fine, the car dies. So it must be sucking air in from somewhere intermittently...... Am I on the right path here? Any ideas what to start checking?
Thanks
My 1979 will idle perfectly when in gear one moment, then suddenly it drops to 300-400 rpm and the car shutters and shakes. At the next stoplight it may or may not do it. It changes from a good idle to shaking and shuddering with no rhyme or reason.
I've rebuilt the carb, no change. I've checked the timing, adjusted the idle mix screws using a vacuum gauge, I've inspected all the vacuum lines. I just can't find anything!
One clue that makes me think it is a vacuum leak, is that when it starts shuttering with a low idle rpm, I can place my hand over the air horn and the idle picks up and smooths out. If I put my hand over it when it's idling fine, the car dies. So it must be sucking air in from somewhere intermittently...... Am I on the right path here? Any ideas what to start checking?
Thanks
