I have a 1995 BMW 540i that started having a rough idle in cold weather. Then car lost a ton of power. It got to the point that it didnt start at all. Had a new fuel pump and fuse, master cylinder and belts replaced. Car still has check engine light on. OBD code is 1222. We were running it with regular unleaded. Car continued to buck and shudder and would barely go above 10-20 miles/hr. The car almost comes to a crawl on hills. The more gas you give the worse it is. The exhaust smell has a very strong gas smell. Not like rotten eggs but overwhelming smell of gas. Now car will not start at all. Any ideas?

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: About Oxygen Sensors

Code 1222 means that the Oxygen (O2) sensor is detecting a very rich or lean condition. This could be caused by a faulty O2 sensor, or it could be caused by a huge vacuum leak somewhere in the engine. I would perform a check for vacuum leaks in the engine - I have an excellent article on this here: http://www.pelicanparts.com/techarticles/Boxster_Tech/21-FUEL-Vacuum_Leaks/21-FUEL-Vacuum_Leaks.htm I would also think about replacing the O2 sensor as well - that might help clear up the problem.

- Wayne