hi bustins4, im also a new e-trac user, been using it since last weekend. trust me, the e-trac will pick up dimes at 3-4", you will not miss them. you might have your sensitivity cranked down, or you are "blanking". if you pass your coil over something that the detector reads in the "black" area, the detector will blank out for a second. also like the guys said the coil might be on edge or tilted. which will change the reading a bit.
from what ive found in the short time ive used the detector is everything is not "cut and dry". you need to get out there with it, listen to it, try to understand it, and dig dig dig....thats how to get a feel for what its trying to tell you. also, dont get overwhelmed by the information it is going to tell you....its kinda like listening to someone go into every detail telling a story....everything is the "long version"
my old detector: "beep"
e-trac: "theres something down there about 5" or so it sounds like close to a coin it has a conductivity like a silver qarter but there is something not quite right about it, from a certain angle it doesnt sound as smooth and the ferrous level is hard to get a good feel on and there might be some iron scraps laying nearby as well." (i dug yesterday, it was some kind of bottle top) "there is so much junk here....junk everywhere...im going to tell you all about everything that is see here and i see A LOT!"
...and so on....
also, at first i was critical of it (just in my mind) until i used it a few times. it had to prove something to me. that it was better than what i had (a whites 6000). im happy with it. it is a better detector.
im just trying to have fun with it....its a very interesting machine. good luck and have fun with yours.