Also the vacuum line for the map sensor looks perfect

 

I believe your engine has a Mass Air Flow sensor (MAF)

After you start the engine , unplug the MAF sensor , what result do you get? When you do that , the computer defaults to readings from other sensors.

If the MAF is defective and it improves , replace the MAF sensor.

 

No MAF on that 86. Has Map sensor. He already checked vacuum line. MAF has no vacuum line to it.See below.
https://www.rockauto.com/en/catalog/...)+sensor,11207

 

I'm starting to wonder if we are getting all,good info on this vehicle.

We don't know where it came from Cal ?
We don't know what if any modifications have been attempted/ done to it,
Is it the original engine,
Did it ever run right and was it sidelined because nobody could get it right?

We will need as much info as possible so as to determine just what we have and compare it to the info we have available
That is one of the reasons I asked for the 8th digit of the VIN, that should at least tell us how the vehicle was built and we can possibly compare that to what we presently have. I have a feeling we are spinning our wheels at this time. What do you guys think? It's a challenge and we all would like to get it running right, but it seems there is a lot of problems we shouldn't normally have.

 

The original owner used it as a farm truck in Texas. At some point about 4 years ago my high school football coach obtained it and gave it to one of my friends. He had the water pump and the timing chain done before giving it to him. My friend doesn’t know how to drive a manual and the heater hose blew out and then he just lost interest. He just gave it to me about a month ago. As far as I know, there were no issues with the truck when my friend driving it for a short tome except for the heater hose blowing out (which I obviously already fixed). There are no modifications to it except for bypassing the inertia switch and it is the original motor. Something tells me that it did have an issue with running rich with the original owner based on him having an extra map sensor and pcv valve. Also when I went to change out the o2 sensor it wasn’t stuck on there like they normally are as if somebody had already replaced it. Just now noticing that it stalls after a high rev.

 

My friend did let it sit for several years before giving it to me

 

Thank you for the requested info.
There are a few things that might need to be checked yet.
Now at least, we have some idea of what we have and what the checks should say.
We will need to either confirm the readings we are supposed to get or just replace the involved parts.
There are a few items that you might confirm are working correctly.
1. are we getting a good supply of vacuum to the MAP sensor? We need to confirm the reference voltage (5 volts) is present there. The sensor outputs a frequency and not a voltage spec.
2. Is the canister purge solenoid stuck open allowing addl fuel to get into the engine?
3. Need to verify system is going into closed loop where computer has control of fuel inj pulse width? If a wire is pinched from past work grounding a signal , that needs to be checked..
4. Is o2 sensor functioning as required ,leaning mixture based on results from exhaust? Might be best to just replace it .
Newer systems provided a means to get this info easily, but the year of this vehicle require that each item be individually tested/checked.
You will need a meter to verify some of these checks, do you have one?
I can provide the specs for the correct readings of most of these.

 

Alright I figured something out. Whenever I start the truck and then unplug the fuel pump relay that is by the air filter housing, it idles perfectly. Seems like a bad pcm to me what do y’all think?

 

I think there is a problem with this .
If you unplug the fuel pump relay the engine should stop running due to no fuel, .
What you may be unplugging could be the intake air temp sensor and that could affect mixture.

PCMs can and do go south, but we try to eliminate all other possibilities before replacing a computer. They can get pretty expensive and are not returnable.

Don't want to go on a wild goose chase , but the computer does supply a 5 volt reference to many sensors and the MAP and INTAKE AIR TEMP sensors are on the circuit.
If there is a problem with either the IAT sensor or wiring it could affect other components that share that operating voltage supply..

 

I know it’s the fuel pump relay. With it plugged in and the ignition in the on position, the high pressure pump won’t stop priming. It runs with it unplugged because the low pressure pump still gets power. If you try to rev it, it’ll die because the high pressure pump has no power with the relay unplugged.