I think it may very well have been the battery. I checked and the voltage was only 12.3volts. I went into the local Interstate battery distributor and they found a bad cell. After a new battery the tach acts "normally" with no delay.
Jake, you were right on, thanks!!

 

No problem. Glad it's working again.

 

Glad to hear it's ok now!
A new battery did wonders for my TT too when I replaced it.

Also, impressive mileage for an '01! I thought my '02 with 32K on the clock was special...

 

For the record, the engine speed sensor, aka, crank position sensor is screwed into the block in the vicinity of the oil filter, and it is a HUGE PAIN IN THE *** to change.

Also, in my case (but maybe not always) the car will crank but not run if the sensor is bad. Heat affects them, my car would start when it was cold, and would continue to run, but if i shut it off and tried to start it hot, it would crank but not fire.

Also, before/after replacing that sensor, my tach takes a second to register.　Every time, always has. I have 159K on the car now, had it since 109K.

 

You guys rock!!
Since the new battery, all is fine!! The tach now registers immediately.....no delay. Thanks for the info AchTTung, on the CPS. I'm glad it wasn't that. I figured it wasn't when I saw the Scangauge registering RPMs yet no tach movement.
Ford 7.3L diesels are famous for having the CPS (cam position sensor) go out and leave one stranded. Most of us oilburners carry a spare CPS in the glove box.