89 Corolla trouble starting

[89toyota2772]

My 89 corolla has trouble starting and runs rough for first 15-20 minutes. I kinda have to stay on the gas to keep it from stalling when first starting it. After that it runs fine and starts fine for the rest of the day. Could it be the distributor cap?

[discnik]

It sounds like a vacuum leak. Can you get a vacuum gage and do a vacuum test on it ? Should be 19-21 inches.