91 buick century 2.5 L 4 cyl high idle

Car runs constantly between 1000 and 1500 rpm. Just replaced ignition module, crank sensor, and timing chain. Ran fine for a day but been idling high ever since. Someone told me it may be a vaccuum leak, but I'm lost. Any suggestions?

I have the opposite problem, idles low, you might be able to adjust it with the screw on the throttle body