I'm pretty frustrated so please don't be offended if I seem unappreciative or offensive.
Scindsin - I got the exact reader from Innova that you suggested, and it spit out the codes I listed above.
What does "calabration code" look like. The tire info etc. sticker is still there. I don't see anything about a calibration code. Trans code G.
OB - Trans Code G -3 speed auto without overdrive - so C6.

The codes seem oddball to me - 91=lean; 92=rich; referencing the wrong transmission, stopping before completing the second round. I changed out the MAP, no change. It died on me and before I shut off the key I heard the fuel pump running constantly, which I read is a symptom of failing ECU. Any definitive symptoms of a bad ECU?

 

Should be on driver's door frame, far left here:

 

I wasn't having symptoms like you but about month and a half ago my computer crapped out. On the driver side you'll see the computer. It's held up in by 3 bolts, one of the harness, and two on the seal. You can either cut a hole in the wheel well (I personally don't recommend this but it is an option) or take the inner fender well loose. Slide the computer out and take out the two screws. BE CAREFUL and DO NOT drop the computer and be careful touching the motherboard. I bet it has a bad/leaking capacitor like most do when they fail. If you decide you have to touch something ground yourself off by grabbing something metal so you don't accidentally shock it. Doesn't usually happen but never can be too careful.

Can't really confirm unless you look at that motherboard and look for burned up components or leaking capacitors. A constantly running fuel pump with ignition on engine off is one of the many signs of a failing PCM. That code on the plug of the PCM you need to take pictures. I recommend just taking pictures in general for later reference. If something is burnt or leaking I recommend replacing BUT it isn't a cheap replacement. They don't make this computer anymore so there are only rebuilt ones. I bought mine for little over 200 but I've heard people get them anywhere from 100 to 300. Check that and please update us so one of us can assist you. If you have any questions spit em out and we'll answer the best we can. Good luck!

 

Mine does not have that sticker - it does have a shiny spot where a sticker was. I'll pull the ECU this AM.

 

Fuel pump running constantly is a definitive symptom of a bad computer.

I seriously believe you have an incorrect computer to start with.

Especially if you are getting transmission codes on a truck with a C6 & spitting 2-digit codes.

 

So I pulled the ECU and it looks like at least one capacitor is bad.

Any place better than others to get a ECU? How do I figure out the correct one if this one is wrong?

I got the feeling I'm (we're) on the right track!

 

That is very possible. I was thinking since it was a 94 it would only be an option for the E4OD but I could be wrong. That could explain some of your issues and I DO NOT recommend the E4OD. I've beat the crap out of mine and absolutely hate it. If one sensor goes bad it gets the entire computer into a frenzy and have to try to diagnose it after work. I'm a farm hand so it's not easy finding time for my own projects till winter.

When my computer went out I was having random no starts, my fuel pump wouldn't come on, and I had major transmission issues. With a bad computer I also fried some sensors throughout the system making it a living hell to track them down with no codes. Does the truck have any other random problems starting?

With the sticker gone you might be able to decode the vin. If someone on here has a vin decoding chart for a 94 please post it here for TNBob. If you can successfully decode it you might be able to tell if the truck has been altered in any way.

 

THE D1X is a 5.8 computer from a 91. I imagine if you open it you will find it is damaged.

Even if it is in good shape it will not get along with your harness and components in your 94.

 

F1TF is going to be an engineering # for a 91 truck.

The computer is wrong for a 94 anything.

 

I have a good 94/5.8/E4OD computer I would sell if you are interested.

 

He has a trans code G he says.

 

Well, that will probably be tough to find...

 

Take that code and write it down. I got my PCM from "The ECU Connection" in Colorado Springs, Colorado for like 240 I think. They had mine on hand and MIGHT have yours. Worth a try if you're interested. Bad capacitor can definitely cause issues. I can't guarantee it's going to fix everything but I could be wrong and it definitely is an issue.

 

Sorry TNBob I wasn't looking closer at your post. That second line of code under the "EEC-IV" is the code you need to look for...unless it's the wrong computer for that setup but could be wrong. Go ahead and search it up to see what you find. A used one is an option but you'll have to go calling local junkyards. Luckily this part is small enough to ship so it could be from anywhere in the states.

 

Here's current rock auto listing 94/250/5.8