engine high rpm

1997 Buick Lasabre V-6. It was running rough and wouldn't idle. Changed plugs and wires, still ran rough but would idle. Short while later the "check engine" light came on and engine would raise RPM uncontrollably. Had to shut down to stop RPM raise. Started engine again, it idled for a few seconds then started raising RPM uncontrollably again with "check engine" light still on.

You need to have it scanned and report back with code(s).