Lock up solenoid 90 d150

Located on the transmission on the driver side.

idle air control needs cleanin or replacin-the motor wears out--inspec whole area and get a haynes manual at parts place for troublshootn

1) FUEL PUMP IN GAS TANK, 2) SENDING UNIT, 3) IN-LINE FUEL FILTER

you may have to replace the computer the charging system also goes thru the computer/

I would check your fusible links. The wires that they are on are what power everything in your cab. Usually they're attached to the starter, the starter solenoid, or the positive battery terminal. Hope this helps!

A Google search netted this:

There is an overdrive solenoid inside the transmission that kicks the OD in and out with the switch. You could have a bad wire somewhere or solenoid is bad.

simple fix. run a hot wire to a battery to a switch then run a wire from the switch to the regulator

have you checked the starter or starter solenoid

possible vacuum leak or bad idle motor

Head bolt torque: 90-100 ft lbs., to be reached in 3 equal tightening steps, below is the sequence:
9 3 1 6 8
Front of vehicle
7 5 2 4 10

Main bearing cap torque: 75-85 ft lbs.
Rod bearing cap torque: 45-55 ft lbs.
Looks like u've been busy, and will be for a while. Good Luck!