haha,you guys...

Dr E is correct it is off the balancer and i believe the gap is 0.50 between the pickup and the balancer.

What do you think would cause the tach to be off like mine, it idles at around 450rpm and I have never gotten it past like 1700.

Have you tried just cleaning and testing the sensors. Theres 3 of them total that need to be cleaned once in a while and you can test them with a voltmeter to make sure they are workin right. Saves the money of buyin new ones and might just fix the problem. They are all pretty easy to get to and you can do the whole thing in less then an hour.

What are the 3 sensors?apps crank and? The tach has been like this since we got the truck and hasnt gotten better or worse.

MAP Sensor. https://www.dieselbombers.com/5-9l-2...-pressure.html

CPS Sensor. https://www.dieselbombers.com/24-val...on-sensor.html

IAT Sensor. https://www.dieselbombers.com/24-val...or-sensor.html