no cold idle speed

[neuton a macaw]

bought used 2006 matrix for wife old 2003 corolla totaled didn't want new parks on street anyhow car when started below 32 degrees has no high idle runs like on 3 cyl ans shakes badly / once u go runs fine till stop shakes till warm / above 32 runs fine till coming to stop /at stop car shake and slowly idle smooths out believe vacuum leak/ how hard to fix any tests or any other though