Don't know if you guys came across this yet, but this appears to be a temp solution, if an aggressive one.

http://modthesims.info/download.php?t=411351

  Sorry guys, didn't mean to guess. Just that people made it sound like once sims start running they never stop, and for me they don't run for very long before walking again. So I thought it might be worth it to get other people to try out the walking mod as a temporary solution because it would be better than nothing. Just trying to help out, man.

  Try this mod: http://ts3.tscexchange.com/index.php?topic=3907.0

 I've been using that mod since before the running disease started, but in my experience when my sims start running everywhere, soon or soon-ish later they will stop.
Honestly I'm not sure if their stopping is from the mod or not, since as I said I haven't fully experienced the issue, but I think it's worth a shot.

My dad's been smoking since he was 13, and he's now 46. He never quit once

 The patch works fine for me, haven't had a crash yet. I have a few nudity mods and an uncensor mod too, as well as several other mods

 Oh and also if bills costed more. Bills are too cheap in the game compared to what sims make, I'd like to think bills would cover imaginary gas and repair costs for vehicles, house heating and water, rent and/or paying off your house costs. It should be harder to make your way in sim-life.

  I don't know how much or what kind of tuning you're doing. But one thing I've wanted the most for this game so far is for careers to be harder and/or take longer. More penalty for missing work and not making the requirements such as handy skill, and boss relationship. And so it takes much longer to get promoted. Maybe also so that raises are less. I have the sim life length at long so I have a few elders that are money machines, they just real in the dough and it seems a little to easy to me, especially when they're getting constant raises making more and more.