GMC Repair: 95 Regal quit running while driving, mr lacey, gm cars

Question
Mr. Lacey,

I've got a '95 Regal that just quit running during a turn yesterday on my way home from work. No sputtering, no weird behavior or noises, just like someone turned off the key. Now it will not turn over, doesn't even try. Just a "click". The battery has 12.57 VDC and all fuses are good.  I went back by the car (dead on the side of the road) to pull it to a garage for the night. Well, I got in and tried to start it, but nothing. Put it in neutral to pull it, then decided to leave it there till the morning (today). Put it back in park and tried one more time and VAROOOOOOM! HOWEVER!.....one more symptom. While driving it from the dead spot to the garage's parking lot, I noticed the tachometer fluctuating, but the motor RPM wasn't really changing.... like quick spikes from 1K up to 3 or 4K.... obviously an erroneous electrical readout. Does this lend to any one problem?

Could it be something in the gear shift? An interlock or something?

I also read about a "crank position sensor" on another site, could this be my problem also? Could that cause the tachometer problem?

I'm afraid I'm going to pay for a diagnostic and they're going to find nothing wrong and then it'll die on me again.  

Answer
hello bob
of course they are going to do a diagnostiac test which i would do in my shop to . 'now i do know it is the crank senser it is gommon in gm cars . proulbly will not show up on thire diagnostiac and the tact will go grazzy have them change it if they do not find any thing . good let and let me know . please rate my serivice pete