2001 Saturn L300

Engine Performance problem
2001 Saturn L300 6 cyl Front Wheel Drive Automatic 86000 miles

My Saturn after reaching operating temp. Will buck while driving and stall at idle when in gear. When I had it scanned no error codes came up all passed.I had it scanned again and it said lost communication. At my wits end. Thanks!
April 3, 2010.

Couple things I'd like you to check is fuel pressure, and the mapp sensor, I'll send you info on how to do a fuel pressure check. I suspect a possible fuel restriction.