1995 LSS engine code diagnosis problem

Hi gang,
I recently purchased a 95 LSS (3800 supercharged) that gives me a periodic check engine light. It has 180000, runs smooth, no stalling, stutter or other performance issues, 22.6 MPG at last check (mostly highway). I assume it's the O2 sensor going south since its intermittent but I want to confirm before laying down the franklins. I find the ALDL under the column and see that I cant stick a paper clip in it to read the check engine light. I take it to my buddy who has an OBD II scanner. He gets an error code and can't read it. Turns out that the car has the OBD II ALDL port but is actually an OBD I system according to the emissions sticker. I take it to my local autoparts store to have them read the code and they tell me that there MUST be something wrong with the ALDL port because they can't communicate with the engine computer. In addition to that he tells me that my engine VIN # (which is 1) doesn't even appear for 1995 models. Has anyone else had this happen to them? I have a Mitchells manual CD rom set that says a "tech 1" scanner must be used. How do I read the engine codes stored in the computer? Does this have to go to GM to read the codes? I figured 22.6 MPG was pretty good for a supercharged 3.8.

Any help or insight would be appreciated. If it's anything like my turbo regal, it eats O2 sensors every 10,000 miles. IF I ONLY WEREN'T SO CHEAP......
Thanks in advance

Thats a tough question. 1995 was a transition year where some cars were OBD1 and some were OBD2. So It's hard to tell. Also you might have a late year model where you have some parts from two different years. Although as far as the computer goes, I haven't heard of a mixed system. It's probably a smart bet to take it to a dealer this time and ask some questions on what exactly the computer system is. As far as your regal goes, it sounds like your egr valve is plugged at least partially. Many times when we get a faulty O2 reading, we find the egr vavles are causing a false reading. O2 sensore usually don't go bad that often without something upstream being faulty.

1995 88/LeSabre/Bonneville are early OBDII which in the case of my scanner, manufactured by AutoXray, has a manufacturer specific cable which uses pins 5-6-7-9 while standard OBDII cable uses pins 2-5-7-10-15-16.