What were the DC values at closed and wide open throttle?

What other parts have been replaced so we do not have keep guessing what you have already done?

 

The truck has all normal maintenance done to schedule. That means pretty recent Oil, oil filter, air filter, trans service, rear end service, radiator service, brakes, front wheel bearings. Plugs, wires, cap and rotor, belts, thermostat. TPS, O2 sensor, Capacitors on the ECU, Trans solenoid pack connector checked and cleaned. No codes in the computer and no lights on the dash. I might be missing a few things.

 

E4OD shift tables are controlled by two things. TPS and Vehicle speed. That's it.

So there are only 3 possibilities:
1. The computer is not receiving the correct vehicle speed (generally they will shift late not, not early)
2. The computer is not receiving a good TPS signal
3. The computer is bad (but not likely if the engine runs fine)

 

I checked fuel pressure today, truck running at idle with no vaccum to the regulator.

Front tank 52psi
Rear tank 58psi.

The truck runs the same on both tanks as far as I can tell, if there are a few extra tenths in the quarter mile I wouldnt notice on the sundial used to time this thing.

 

That fuel pressure looks pretty good.. well within spec. Is there any evidence of chewed wires anywhere? You say the PCM had the caps replaced, had any of the originals exploded when this was done? If so it's possible other components on the board were damaged so it may come down to replacing the PCM.

 

If you're getting two different pressures front/rear, during the same test run with the vacuum line disconnect, I'd suspect the front FDM is starting to fail. 6 PSI is a big discrepancy at idle that probably turns to 10+ under load.

But that's another issue all together. Low fuel pressure will not change your shift points.

 

Even though the speedo(PSOM) is working the movement properly, it still can send bad speed info to the ECU and factory cruse control(if you have it). On my 95 E350 bus, the PSOM did send bad speed info to the ECU and caused hard/weird shifting and cruse control would not hold speed. But it never showed on the needle's movement.

When the problem is occuring, watch the OD lamp on the end of the shifter. It may start blinking and that means there is a issue with the E4OD part of the ECU. Most likely speed information related. Also test your cruse control(if you have it) and see if it will hold speed.

It looks like the ECU is seeing speed over 80MPH and that's why it will not downshift and also hits that stupid speed limiter.

 

Oh I missed that.. I just glanced and thought they were the vacuum/no vacuum pressure. Yes pressures should be the same front and rear.

 

This is good info here. I dont get any flashing on the OD light, and the light does work. I also dont have cruise. I think I need to check into this device a little more.

 

truck shifts from 1st to 2nd to 3rd to 4th really early

The PSOM in my 94 cause that very issue, I live on a rural highway leave the driveway it'd be in O/D before I made it 100 <strike>yards </strike>feet down the road.

And yes my speedo needle was rock steady.

Had other issues with it yours doesn't appear to suffer with that however yea sounds like it'd be highly suspect without them regardless.

 

You say you do not have any codes in the KOEO & KOER self-test but did you let the KOEO self-test run all the way to the CM stored codes.

You can have 111 on both KOEO & KOER and still have CM codes.
We need to know about all three sets of codes.