[Shotimes] Crankshaft Position Sensor?

[(Test) Beckers, Shawn]

I have a 94 SHO and have had a problem for a little while now where it will sporadically stall while driving and then won't start (that is, the engine turns but doesn't start).  If I leave it sit for a while it will then usually start.  Also, sometimes while I'm driving the check engine light will come one, the tach will go to 0, and the car won't respond to me giving it gas (even though the engine is still running).  All of this only seems to happen on warm days (I'm from MN so that doesn't happen very often).  To top it off, the fuel efficiency of the car has been horrible since this all started happening.
 
I had been puzzled by this problem and wasted a few bucks having a mechanic try to troubleshoot it (he told me it was the PCM and after replacing that didn't solve the problem he said it was the fuel filter) when I just happened upon the SHOtimes web site today.  Low and behold there was an article dealing with the crankshaft and camshaft position sensors which seemed to describe my problem.
 
Now I have two questions.  First, from the description of the problem I've given, do you think I should be confident that the crankshaft position sensor is the problem?  Second, can anyone give me a ballpark figure as to how much it may cost me to replace this?  Unfortunately, the good lord didn't bless me with a great deal of mechanical ability and after reading the article on how to replace the crankshaft sensor I think I had better let a professional handle this.  And, since I've had problems with the Ford dealership here I plan to bring my SHO somewhere else, but want to have a rough idea of what the problem is and how much I can expect to pay to fix it.
 
Thanks in advance for any help/advice you can give me!