Vacuum Problem
 

My runner is idling rough and it was suggested it may be a vacuum problem. The guy who installed my engine tested for leaks. How would I go about diagnosing/fixing a vacuum problem?

use some small hose lying around and replace the vacuum lines one by one until you find the problem. That may work, not sure tho

Check to see if the throtle body is sealing. That was my problem and it took me a year to figure it out!~

spray some carb cleaner around all the vacuum hoses one by one with the engine running..............if the idle jumps up when you spray you have a leak at that hose