Greetings to all at BuickForum.com. Re: '95 LeSabre Limited. For some time now, I have been experiencing a "check engine" indicator. There doesn't appear to be any negative effect on the operation of the vehicle. I have been to several auto places that offer to read the computer free of charge. None of them have been able to get the reader to communicate with the car computer. I found out later that my car has an OBII connector with a OBI system, so in effect, the connector for the reader doesn't provide power to the reader. So, the reader must include a plug in of sorts to a power source. GM refers to it as a Tech I reader. I know I can go to the dealer and get it read for $80 but being on fixed income, it's not in the budget. I am able to fix anything on a car except the trans and limited underneath work and I consider this forum and it's kind knowledgeable members among my toolbox. I went down the list of the simple things that can cause the light to come on and among that list is to replace the oxygen sensor which I did. After that I proceeded to clear the computer by disconnecting the battery ground for, at least, 30 secs. After re-connecting, I started the engine and eventually, the light came back on and too, now my a/c doesn't work right. I get air out of the floor ducts and the windshield but not the instrument panel ducts. If I leave it set on MID, I might eventually get air out of the panel ducts but probably not. One thing that stands out is when I do get air out of the instrument panel ducts, the flow diminishes when accelerating, especially if going up an incline. So, now I'm wondering if my "check engine light" problem might be in the vacuum system somewhere. Anybody? Thanks