Need Help To Identify A Grey 3-Prong Plug Underdash In 1990 F-250, 4x4, W/Manual Transmission, 351W

A 3 prong mains plug? It might be a block heater?

Wiring diagrams, but really you need a Service Manual.

https://www.google.com/search?q=1999+Lincoln+continental+wiring+diagram

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u can leave the (earth) wire

If it's a California truck it's a good chance the ignition is EEC-III (brown grommet on ignition module.)

The EEC-III distributor rotor fires alternately from both sides of the distributor rotor.

The the spark plug wires for an EEC-III distributor will be wired counter clock-wise in a different order.

351w firing order, CCW: 1-3-7-2-6-5-4-8
351w wire order, CCW: 1-5-7-8-6-3-4-2

I would think you were given the wrong fuel pump

If it was the correct pump ,you would have update
instructions that would guide you & also answer your
question

Hi there:
I suggest to check this diagram on...
Ford Engines: 5.0L HO, 351W, 351M, 351C, 400




Ford Engines: 5.0L HO, 351W, 351M, 351C, 400:
Rotation: Counter-clockwise
Firing Order: 1-3-7-2-6-5-4-8

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

Hi there:
I suggest to check this diagram on...
Ford Engines: 5.0L HO, 351W, 351M, 351C, 400




Ford Engines: 5.0L HO, 351W, 351M, 351C, 400:
Rotation: Counter-clockwise
Firing Order: 1-3-7-2-6-5-4-8

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

It won't work. The 1996 one has an electronic governor. The older ones have a hydraulic governor, they aren't interchangeable. Sorry

I hate to be the bearer of bad news, but that transmission from the 94 won't work in a 96. Probably because the 94 was for a Jeep with OBD I and your 96 has OBD II. I checked my used parts site and all that will fit is a transmission from a 96, maybe a 97.

Here is a listing of all possible computer modules for that truck. Perhaps this will help in some way in your search.

Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AL1A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AL1B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AL2A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AL2B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-ALA
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-ALB
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AN1A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AN1B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AN2A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AN2B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-ANA
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-ANB
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AP1A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AP1B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AP2A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-AP2B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-APA
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Calif, ID E8TF-APB
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), High Altitude
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AK1A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E8TF-AK2A
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E9TF-Z1B
Elec Cont Unit (ECU), 8-351W (5.8L), (AT), Fed, ID E9TF-Z2B

is it a 3 speed or 4 speed trans if a 3 speed you can unplug the square 4 prong plug on front of trans it's reachable from the top you may need ta remove breather.DO NOT TRY THIS ON AN OVER DRIVE UNIT IT WILL BURN UP AN OVER DRIVE.but if it's a 3 speed it won't a thing the plug works the lock up in the torque converter it sounds like the lock up is the problem if it's an over drive you will need a transmission man to have a look at it. hope this will help you..