After years of looking, as of August 2007, I have resolved the Porsche 944 shudder problem for years 1985.5 to 1989. I had just bought an 1987 Porsche 924S and was finally able to focus on the solution. Yes, late 944 do have the same engine shudder as the early 944. The late 944 shudder is usually less severe. The shudder also effects Porsche 944 Turbo, 944S and 944S2.
After 6 years of looking, (not the whole time naturally) I found the area of code that controls the fuel cut-off on deceleration. See the chart below. I increased the rpm values for fuel cut-off, as I did with the 1984 DME six years ago, and the shudder is now gone!. I was driving a 1987 Porsche 924S at the time and it was so enjoyable to drive after the fix. I drove it for hours going no place in particular and had a great time.
See the 1984 shudder page for a more detailed description of the "944 shudder".
I have Shudder fixed code for all stock 944 models. There is no charge. If you have access to EPROM programming equipment and want to make your own, send me an email. I will send you the the shudder fixed code. Again, there is no charge.
