What went wrong with my o2 sensor?

[smarandi86]

Hi everyone. I recently just got my head cover valve (gasget) changed along with my crankshaft seal. I have a 95 325i with 127k on it. When i picked it up from the mechanics and started the car, i noticed a kinda white smog coming out the back of my exugst. that does happen when the weather is cold out, but i've never seen it white like that. Anyways, the next day my check engine light came on. i took it back and we figured my 02 sensor went bad. could this have been something they did wrong, or is it typical for an 02 sensor to go bad after awhile? It cost me about $230 to get it fixed. it only took 40 mins. Also to add to my problems, my car had recently started to shake (rumble) when starting the car cold. It will do that for about 15 secs, then smooths out. Could it be my cold start valve? sometimes i'll turn the ignition and it will stall in starting (sounds like its clogged). the car doesn't fire up right way. i have to hold the ignition. Should i just sell this car while its still working?

[WarNox]

For the shaking and not starting it could be that your ICV is dirty and spark plugs could be old! check that out first!

[Teh Prof]

O2 sensors go out with some regularity on our cars.