1965 cadillac 429 cu in. Crank case tube under intake disconnected.

Any fault codes?

Here are the most common causes of idle surge, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

If you disconnected the battery you have lost what we call "learned Idle", read below on problem and solution.

Here are the most common causes of idle surge, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

The ignition points in GM Delco distributors are adjustable while the vehicle is running. Although I have not found any specific point gap stated for your 429 ci engine, the instructions say to turn the adjusting screw clockwise until the engine starts to misfire, then back out a half turn (footnote 5). The most accurate way to set the point gap is to use a dwell meter to set the dwell angle at 30. I recall mine was fairly inexpensive (about 35 years ago), but I don't know if they are even available these days.


1965 75 Cadillac Tune up Specifications

Here are the common cause of surges, stalls at stops, slow idle speed, erratic idle, it is in most cases the idle speed control air-bypass valve and/or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving

try to choke air at carburetor a little bit until it stall if rpm go up or running better then you have a vacuum leak ,or carburetor rebuild
hope it helps

will not make any difference on a vehicle of this age other than a horrid smell when stationary of hot acrid oil fumes

Check all the vacuum hoses to the large black intake tube.the crank case breather tube used to come off, causing rough idle, stalling and hesitation.

The starter relay is on the drivers side of the engine compartment behind the air filter housing under the fuse box cover

Try this
Here are the most common causes of surges, stalls at stops, low erratic idle speed, rough idle and engine hesitation, it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

Here are the most common causes of surges, stalls at stops, low erratic idle speed, rough idle and engine hesitation, it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.