1994 Olds 88 Royale tranny problem coasting shifting to OD

[jphess]

I am having some issues with that 94' Olds 88. It has been happening for about 4 months and is getting worse. It started out as just intermittent shuddering on the interstate and now is shudders slightly all the time.
Under load it is almost like it is losing power, but it isn't. It will shift down under load when accelerating quickly.
A few items that I have done (before getting to transmission):
* Have replaced plugs and wires
* Checked spark on all plugs to test the coil packs - all fire "hot" at various throttle speeds
* Checked all vacuum lines
* Replaced fuel filter
* Check fuel pressure (stays at 38 - 40 at idle and under load and is constant)
* Checked voltage and resistance at each injector (googled the
procedure so don't know what the measurements were - repeated process twice with same results)
* Replaced MAF sensor up by air filter (it was bad per required measurements)

From the above, I would ascertain that it is not air obviously. Fuel seems not to be the issue. Spark has all been checked.
The 94 model has that stupid ODB 1.5 that some 'brainiac' came up with. Only 94 GM had it. I can't find anything that will hook up to the computer to get a good reading. I even tried different software on my computer to gather a dump, and it will not sync up. So, I have not ruled out a computer issue.....then progressed to the following items.....

Other facts:
* Started out as shudder on interstate under load. Once load decrease at top of hill or on flat, it settled down
* It then progressed to what it is now where when accelerating it seems to be fine and once OD kicks in, it starts shuddering bad. This is constant now so not driving.
* No matter if it is in gear or not, it will run rough when giving it gas (sounds like it has a bad plug)
* Does not slip
* Transmission fluid is clear red and does not smell burnt. Filled right to mark. (Have not changed filter yet, but have one in shop)..I know this is next step.
* There is a "ticking" that you can hear above and below the engine. It appears to be louder underneath the transmission. The ticking is happening all the time whether at idle or in gear. It does not sound like it speeds up when acceleration is applied. When the ticking progresses at time it becomes more of a loud rattle. It can get very noisy at times to where it sounds like something is going to fly apart.

I was reading online and a few others have had the same issue. Many stated that it could be the TCC solenoid in the transmission that will cause the OD not to lock up. Others stated that the torque convertor may be bad. Both make sense, but this is not an easy fix since replacing both means pulling the car apart to drop the tranny. I am looking for other opinions before starting the drastic stuff.

Car only has a 110,000 on it so not ready to give up hope. Any expert thoughts?

[BillBoost37]

Like you, I'd enjoy a data stream to see what the pcm thinks is going on.

Being a 94.. I wonder about the pcm. 94 and 95 were by far the flakiest years of pcms. But..it could be a lot of things. tough to tell w/o having any real info from the car.

[jphess]

update on this:
trouble still exists but I did have to replace the computer. There was a fuel injector not firing and I trace the issue back to the computer. Changed this out and all injectors are firing. Now, I have eliminated the computer itself. I still have no access though with the ODB1.

Anyway, the car runs better but the shudder still exists when it goes into OD. When going down the highway, it shifts into OD. I tap the brake and the shudder stops immediately. When the OD reengages, the shudder begins again.

I found a post about this sometime back but I can't find it now. It was referencing a possible solenoid issue, but that is all I can remember. Anyone have any suggestions?

[tytotheler92]

To me, it sounds like the OD solenoid.

I don't know how involved it is to replace on these however.

[human]

Just a slight clarification: OBD 1.5 was used on both '94 and '95 models. As far as I know, the only difference between OBD 1.5 and OBD 1 is that OBD 1.5 uses the OBD 2 style connector but most of the pin sockets on the connector are empty. Everything else is pretty much identical. And yes, it's next to impossible to find a scanner that will hook up to it and give you any data.

[MKMike]

Autoxray 5000 and 6000 are said to pull codes from your type of system (OBD I system with OBD II connector) and the Actron CP9145 and 9150 are reputed to do the same.
Before making a purchase, I would contact the manufacturer just to be 100% sure.
Ebay may be the cheapest source.