Ωhm

Is that for both the front and rear running lights? If front only, double check the grounds on those two trailer light assemblies. Ground through chassis or wired to ground.

1987 Electrical Manual

Connect ohmmeter between oil pressure sender terminal and battery ground terminal. Resistance should change with change in oil pressure. Note values. I might have a spec sheet somewhere.

I've always like it when a crane does this during its off time. Happy 4th.

I like the story of 1-2-3.

Do the Hazards work? If not, double check the hazard/stop fuse.

Nope. This was mine, buried in a box, buried in the basement. Went back to the house (boy lives there now) looking for some vintage lens for my camera, which I didn't find.

Idle Air Control Motor Tester (4.0L)

Belt routing, correct? Belt tension, correct? New/old belt? Check and make sure that the belt is not just slipping.

Distributor needs to be indexed, not timed. CPS determines set base timing. ECU will advance timing, based on inputs from that set base timing mark. Cruiser Tip 13; Distributor Indexing

Okay. Just needed to be sure your fuel pump wasn't getting its voltage just from the Starter Relay during CRANK.

D1_5 & D1_6 would be fuel pump circuit tests. D2_4 checks for IGN SW (I1) voltage. Do you have the fuel pump ballast resistor?

Yes. You should see voltage (B+) on those pins while cranking. D1_5: Fusible Link for Fuel Pump Relay. D2_4: Ignition Switch. D1_6: Fuel Pump side of the Fuel Pump Relay.

Using a voltmeter or 12vdc testlight (preferred) check for Battery_Voltage_(B+) on the following pins (use battery_negative terminal for ground): D1_5: B+ (Hot at all times) D2_4: B+ (Hot during KEY ON/CRANKING). D1_6: KEY ON (B+ (Hot for 2-3 seconds)) or CRANKING (B+ (Hot during CRANK)).

Keep us posted on this one.

Your DVOM (W2974) should serve you well with 12vdc stuff, but maybe not so good with 'turned on turn signals'. Your friend gave you good advice about using the circuit tester (aka testlight) for what I was trying to do with a DVOM. So, if that circuit tester blinked brightly like a turn signal (TEST 2) then vehicle and vehicle wiring has tested good. Seems to me, problem lies within the Instrument Cluster, even though it has also tested good. Check/replace BULB holder socket. How that for help.

photo @cruiser54 Note TPS with ECU and TCM connectors. Is yours like this one? If so, then you got the manual Engine Control Harness which would be blank at C101_C1, C101_C2 and C101_C3.

Did you swap out the Engine Control Harness when you went with the manual trans?

Auto or manual trans? If manual, do you have the 3pin and 4pin connector for the TPS circuit?

Trigger wheel radial runout is 0.016 inch (0.40mm) using a dial indicator on the inner surface. Check out page 77 or 2A-15

Take that air bonnet (aka ADAPTER, Air Intake) off at the throttle body and make sure you're not starving on air. Look/make sure the throttle plate is moving.