ok so i have a problem with the computer not cutting the ground to the coil. the test light stays on while cranking the whole time until you cut off the key. it does it normal power for 3 seconds then shuts off when key is not in start position. i have replaced computer and problem still exist i have also changed cam and crank sensors. i also found that with the heated oxygen sensor pluged in i have continuity to ground from coil positive of about four ohmss i unpluged the oxygen sensor and now there is no continuity to ground from coil positive. but the truck still wont start.

 

It could be tons of possibilities. Do you have any Check Engine Light Codes?

 

nope no codes the computer is reading the crank and cam sensor though as all injectors fire in sequence as motor rotates. and i noticed now the tach dosent work right but the cam sensor switched 5.0-0.0v as the motor rotates same as crank sensor. i have noticed the no tach after i changed in a new computer

 

Been there, done that
Could be faulty hall effect pick-up coil ( under dist. cap )
-bad ground between computer and fuse panel
-faulty splice between computer and fuse panel
-bum computer ( it happens...even to new ones )