Ok, so it first happened the night of the last Hillsdale g2g when I drove my Lumina. I noticed going uphill it would almost "surge" at times... My first instinct felt like the transmission slipping, but it would only do it around 50mph going up hills, so I concluded that it must just be changing gears and nothing more.
Well now the other day I notice the car seems to be idling somewhat rough. Every 5-10 seconds or so it will "hiccup" but very slightly...not really even noticeable if you aren't in the car, or listening to it. Doesn't sound like it's going to stall or anything.
Well the other night I was coming home from work, and where the speed limit goes from 45-55 I was accelerating, and it started surging or sputtering until I got to speed. It probably did this 4 or 5 times.
Well today I was coming home from school, on the expressway going about 70 with the cruise on and it started doing it again. This time it did it the whole way home, surging and having a hard time maintaining speed. It would slow down, speed up, slow down, trying to hold the cruise speed. One thing I will mention, is just 5 minutes before I had to drive through a deep puddle, and smoke was coming out from under the hood like water had hit the engine... Don't know if that could do anything to trigger this or not...but I don't know since it had been doing it before when dry, now it was just worse.
So I've looked online, and it can really be anything. The car was tuned up when I bought it (2006). I put a new air filter in '07 or '08, and I checked it and it's clean...very clean. I had just put a new fuel filter on this past fall, so I really don't think it would be that. I couldn't see any cracks or anything on any vacuum hoses...
Does anyone else have any ideas?
EDIT: Also, I don't know if bad gas could be anything to do with it? The last time I filled up was before I left for Florida when I put it away. This would have been 5-6 weeks ago. I have about half a tank left, so hopefully I can use it up soon.... Wouldn't have thought it'd get that bad that fast, but who knows since there wasn't any type of stabilizer in it...and it was full. Although this wouldn't explain why it did this in Hillsdale/Hudson, but again that could have been my first thought...gears shifting.