With the hood open and an assistant in the car have them push the throttle peddle down. Does the engine noticeably rock? Your engine mounts could be bad.
If you have some sensor problems then you should be able to find a DTC Diagnostic Trouble Code that will get you going in the right direction. Depending on the scan tool, many of us find the Crossfire will scan as a Mercedes 2002~2004 year SLK 320 if you have a Limited or Base car and a SLK 32 if it is a SRT6.