Too high compression (Saturn)

If it's a 1.9L normal compression is 180-205 psi. Never saw 225 psi. Check ignition coil and intake gaskets. They are the most common problems with a rough running engine. Especially the intake gaskets. Your engine is in the mileage range for a bad intake gasket. Spray carb cleaner around the intake manifold and see if it changes the way it idles. By the way every Saturn I ever worked on that had a bad intake gasket was #4 cylinder runner. Tough to dope out problems on these newer cars without a scanner.