1990 Deville skiping and running rough

Here is the story.

Was running real rough and we changed the plugs thinking they were fouled but found that they were soaked with gas. We then plugged into the computer and found that the MAT was at -36 degrees and the CTS was at -34 degrees. After a few checks we determined it was a bad pcm and replaced it. With the computer pid info all looking correct now it still runs rough. We put it on an ignition anylizer and all the fireing lines look correct but when doing a power ballance test we find cyl's 1,5 and 8 all are low compared to the rest. So we then went ahead an did a physical compression test and all were good and close to each other and about 150 pounnds or so. we again replaced plugs and this time also the wires but the car still runs real rough and feels like it is running on 5 cyls.

Got any ideas for us?

Thanks in advance.

Welcome to AF. Dist cap?, also if this is a port injected engine, the injectors are another possibility.