have you checked the hall effects sensor in the distributor?

 

Don't discount rodents as the little cheese thieves are sneaky. However, as often as you've had the wires off, maybe a couple are crossed. Is the misfire regular or intermittent? How does it misfire? A dead pulse or fire out the throttle body?

When you say you have the factory fuel pump, I'm assuming out of the truck. Are you using the truck tank too? Did you use ONLY modern fuel line hose? It must be modern hose designed for fuel injection and alcohol fuels. Even 10% ethanol eats older rubber up. Hence asking how it misfires as a injector with rubber particles will cause a misfire..

Not being there to look at it hinders diagnosis. You might have something simple like a bad ground. I've seen a bad ground from the engine to firewall cause major problems. Got any photos of your set up?

 

Hopefully this can clear up some things.

 

wait that is a 318 magnum which is out of a 92 or newer. have you tried spraying quick start into the throttle body before cranking it? you may have fuel pressure at the rail but still could have stuck injectors.

you say you replaced the computer but did you order one for a 91? if so that may be the issue.

 

Is the speedometer the one out of the donor truck? Your engine is off time. That's what that grunt when you try to start it is. It spins, grunts, then spins. Check for slop in your timing chain. Pull the distributor cap. Rotate the engine by hand until the rotor is at the #1 position. Make a mark with a sharpie or some other marker but NOT a pencil. Pencils are made of graphite and WILL cause shorts in the distributor. I usually use either a sharpie or soap stone. Now mark your timing mark on the balancer. Rotate the engine by hand backwards. See how far it goes before the rotor starts to move. A couple of degrees isn't a problem. 5, or 10, or more is. In that case, drop a new timing set in the engine. 130K is a little early but if the oil wasn't kept changed, it may have worn the chain. Engines in constant use don't have a problem but one that sits, can jump the chain a tooth. That will sound exactly like what you have. This will be neither fuel or electrical.

Fortunately, unlike modern cars, you have plenty of room to move the engine and check the timing.

 

I think your right. What year computers would work with it?

 

a 92 or 93 computer should be what is needed for a 318 magnum. i believe they have the same connector as a 91 so it would likely hook up but it won't have all the parts to fire all 8 injectors since it is only made to fire 2. should likely be able to verify this with some quickstart or gas down the throttle body.

 

I poured a bit of gas into the intake and it ran a little bit

 

It's possible something else is wrong, but I would bet money (and I'm notoriously chea...er...thrifty) your engine has jumped time. If you manage to get it running, it won't be able to get out its own way. Check for slop. You my even see the rotor at #1 but the balancer timing mark is off from TDC.

 

Wouldn't the computer throw a code if that happened?