You do not need to hold it down at all,Sensor goes in and stay like that and clip will go right in with out holding sensor. So as I mention something is not right.The oring is out. The whole seems clean. I can get it in but I cannot hold it in which seems necessary to keep it down far enough for the clip to catch and hold it. I am going to attempt to take the aluminum? intake tube off that is above it even though no videos I have watched shows them doing that. I think then I can hold it with my right hand while I place the clip with my left. Otherwise I will have to try to find someone to come to help me OR tow it to the dealer. I am feeling pretty stupid for even trying to do this myself.
YesI sounds like there is still something in the "hole" , as stated by Jetta 97, do you have the old sensor ; try that one again just to see if it fits. If not, then there is something blocking the sensor from seating properly ; if it does seat, then you have the incorrect part. (??). Photos would really help as noted in post #8.
Is this your part ???