This is a long post, sorry
I too have a 92 Lumina with the 3.1, just hit 103K miles, replaced battery about a month ago, previous one had been in for 8 years and finally just couldn't turn it over in the frigid cold. Each time I've disconnected the battery, and then reconnected it, the first starts have been really rough. This last time, I had to pull the whole air box out, but I didn't remove the intake plenum. Took it for a drive and came to a stoplight, it came to a stop and then engine just died out. Started back up and things seemed fine. It starts fine, when it's cold it sounds like it runs fast, like high idle, then when she warms up, it drops into low idle. Couple weeks ago, I left it idling while I ran into work real quick, came out, and the engine wasn't running, key still on. Started right up and ran fine. Last week, I put a sirius tuner in and was sitting in my driveway getting everything dialed in, and it died out again. Just turned it off and went inside. Took it to friend's house and it did the same thing, this time I had to get to work, so I tried to start it back up and it wouldn't start. It would turn over fine, and fire a little bit, but it wouldn't fire up and run unless my foot was on the gas. Radiator fan was running, and I believe it dies everytime the fan wants to kick on. Every other time the fan would come on, the engine would bog down a little and then return to normal, probably because of the current draw. This time it's enough to stall it out. I was sitting at a stoplight today after driving for about half an hour, quite a long light, and it died again, put it in neutral, left foot on brake, right on the gas and I managed to fire it up right as the light turned green, put it in drive and off I went. Noticed it didn't have much power, and oh...NO SPEEDOMETER. #@$)! Something's really messed up now. Got it onto the freeway and it didn't want to shift, but reluctantly did after babying it and holding up traffic. Speedo shot up soon after...then speedo dropped back down about a minute later and shot right back up. Also worth noting, last night I did a reset of my IAC, thinking that might have been the cause why it was idling too low to run the alternator under heavy load. I don't have a tach, so I wasn't sure how fast it was running, this was the third time the IAC reset and idled fast, the first 2 times I didn't know what was going on, so I put it in gear and it calmed down. Last night, I reversed out of my driveway and went through neutral, was still running high, slipped it into drive, check engine light flashed on then off for a split second, and then the engine came into idle. Thought everything was good. If that's not right, please let me know. That's the ONLY time any of my indicators have come on, except when it dies and all the lights come on. None of them came on today while it was driving or any other time. I suspect that I have a problem with my ECM/PCM. I know this is a lot to read, and I hope someone can give me a better idea of what the problem is. If any of these symptoms sound familiar, please volunteer any info you may have. It's a great car, no rust, surprisingly for a MN car, 12 years old, 103K miles...engine pulls like a son of a gun when she runs right. Everything with the air box assembly and plenum is back together and tight, so I don't suspect any leaks. Please help
~~DJ