So I just did some tinkering and made an odd discovery. Today I decided to complete redo all my vaccum lines because half of them where cracked, broken or just missing and now it barely runs. It will barely hold idle with everything hooked up but if I unplug a couple of the lines on the driver side from the intake manifold, the idle picks up and it runs better but it still stalls when put in gear.

 

Have you cleaned the throttle body?

 

I did, I took the throttle body and the intake manifold apart and really cleaned both of them all up good.

 

What spark plugs did you put in?

 

So when I first got the truck I put in some real fancy expensive iridium ones but this time around I went cheap and got some champion copper plugs

 

The coppers are correct. These trucks don't like the rare-earth plugs much.

Do you have a scanner that can read live data?

 

Not one that can read obd1 I have an OBD 2 scanner but obviously the plugs are different

 

Without it, you are only going to be guessing. That can get expensive VERY quickly. Know anyone that has one? The other alternative would be to take it to a shop that has one, and pay them to figger it out.

 

So I actually just discovered what could very well be my problem. The fuel pump is brand new and I took it out of the tank and tested it and it works but the truck refuses to use it. When I put it back in the tank the other day it worked fine but now I can’t get it to come on. I checked the wiring and the wiring is good but I even tried a jumper wire at the relay and I can’t get the fuel pump to come on so I think the truck is running off the suction created by the engine running but it has no fuel pump. Like I said the pump is new and the wires are all good as far as I can tell. What would cause the truck to not use the pump?

 

Are you actually getting power back to the pump? Maybe a bad ground?

If the pump isn't supplying pressure, the engine won't run. At all. The engine won't suck fuel in.... If it fires at all, then the pump is at least attempting to do its job.....