2001 Check Engine, and

Hi,
Our v6 2.7L with automatic has an issue I hope you can elaborate on.
 
The check engine light comes on and the car jerks real bad when accelerating, or cruising over 70 MPH. Seems to happen more in higher temps or after being used awhile.
 
I had our general repair shop check the engine codes. The check engine light was not on when they looked at it, and there was no codes to report.
 
Thanks for any ideas.  90K miles and we have not done any fuel injection cleaning.

Found out it was the cam shaft position sensor causing the issue. That and worn plugs.  $315.00.