Car sometimes has no power until it gradually reaches 40 MPH then it runs OK. I suspect the MAP sensor is no working correctly but I can't find it even though I have found a photo of it. Where is it located. Any other ideas on what may be the cause of the problem?

well this si the ZJ Forum, you might want to repost you questions here http://www.automotiveforums.com/vbulletin/forumdisplay.php?f=1452

But I will tell you most of the time the Manifold Absolute Pressure Sensor is located on the throttle body.