Go to the "Tech Info" thread atop this forums thread listing page, open it & scroll down & click on 3.0L cam sensor replacenent.
Lots of other good wrench turning info there too.
Be sure to scroll down far enough to find the Misc secton, to also find the 3.0L Tech Info link Rockledge put together, as it also has lots more good 3.0L info.
1999 service Manual states for the 3.0L
Do not turn the crankshaft or the camshaft during the removal and installation or the cam sychronizer (this is the part that goes into the engine and not the Camshaft Position Sensor CMP) or the fuel system timing will be out of time with the engine and possibly cause engine damage.
Rotate the (1) crankshaft until the No. 1 cylinder is at TDC of the compression stroke and the (2) TDC marks lines up with the timing mark. The timing mark being 10 BTDC on the crankshaft balancer.
A special tool must be used during the installation of the replacement sychronizer assembly, Failure to follow this procedure will result in the fuel system being out of time with the engine, possibly causing engine damage.
It is very important to coat the gear on the camshaft sychronizer with Super Premium SAE-5W30 Motor Oil or equivalent meeting Ford specification WSS-M2C153-G or equivalent, prior to installation. Failure to do so could result in gear failure upon engine start-up.
Install the special tool on the camshaft sychronizer by rotating the tool until it engages the notch in the camshaft synchronizer housing and the armature.
During installation, the arrow on the special tool will rotate clockwise until the oil pump intermediat shaft and the camshaft gear engages
Install the camshaft synchronizer housing assembly so the arrow on the special tool is 38 degrees from the centerline of the engine. 38 degrees counterclock wise. So that if a line were drawn thru the tool parallel to the centerline of the engine the arrow would point to the left. about 10 oclock if the rear of the engine is 12 oclock.
If you have more problems than you can handle, check with you local Ford Dealer, he might tow and repair the truck for less than you think.