Posted by Johnd [172.71.222.153] on Thursday, May 18, 2023 at 17:32:56 :
In Reply to: Cuts off posted by Worth in NC [172.71.222.153] on Thursday, May 18, 2023 at 10:36:51 :
My bet is the vacuum brake booster has a blown diaphragm. Every time you press the brake pedal, you lose all your vacuum , and the engine dies.
To test, remove the vacuum hose at the brake booster, and plug the end of the hose. Get in the truck and press the brake pedal at different RPMS while sitting stationary. If the problem no longer exists, the booster is the culprit.
Remember you have the most vacuum in the engine at idle, when the throttle butterfly is mostly closed in the throat of the carb, so an engine stalling from low vacuum would be more likely at lower RPM’s.
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