1983 380 SEC Missing after warm up
 

It seems to have a ruff idel after it wamrs up plugs wires cap and rotor are new. What opens up after it warms up and what could cause a vacume leak. Is what I'm thinking any one have an idea?

The car runs on freeway fine idles ruff after it warms up and I put a vacume gauge on the intake 15lbs of vacume at idle after warm up. New vacume advance also with tune up parts.

15 inches is a little bit low. Trouble is, a poor idle can cause low vacuum, and a vacuum leak can cause a poor idle So to start with, check all vacuum lines and connectors in the engine compartment carefully. Then disconnect and plug the vacuum line at the rear of the intake manifold, and see if that makes a difference. If it does, you may have a leak in the cabins systems (climate control and door locks).

Thank you I went and checked all liones including trans and no diffrence now what? tune up about 1,200 mi ago

plugs,wire bad coil?was it OEM cap and rotor?