Backfire?

Hi i have a 1998, bmw e36 318 UK Model, recently the check engine light came on and it was misfiring slightly, it then backfired and blew the backbox out on the exhaust,i called the local garage and they said fuel must be sitting in the exhaust and hence the backfire, took it in and fault code read o2 sensor and they changed it for a new one. however this did not work and car still mis fires, have had a new backbox and now have a rough idle still, waiting for it to go again and cause more damage, the garage could not explain the fault and advised taking it to bmw which will cost a bomb...... any ideas or advice is greatly taken all other usual routes tried, pipes, sparks, etc thanks

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW 3 Series (E36) Oxygen Sensor Replacement

[Wayne 962]

I would plug it into the code reader and see if you can figure out what the computer is trying to tell you. It doesn't appear that this was an O2 problem (backfiring is not really related to the O2 sensor failures). See my tech article in this section on reading and troubleshooting codes.

- Wayne