1999 BMW 323i missing on cylinder 1 when warm Help appreciated

[sisu-mn]

My 323i runs fine cold, but as soon as it warms up it starts missing on cylinder 1. I've replaced the spark plug boot, but the problem remains. My next thought is to try a bootle of fuel injector cleaner. I normally by 92 octane fuel. Anyone have ideas on what might be causing this and how to fix? Thanks.

[estoril blu]

Possibly coil breaking down when hot.

[drivinfaster]

have you identified which cylinder is misfiring?? try switching the coil to another cylinder. if it misses on that cylinder, then you have a faulty coil. if it stays at that original cylinder, then that would indicate possible other faults. but i would start with the simple stuff first.
fuel injection service was always suggested every 30k, but i have done them at higher intervals depending on the type of service being done. not all fi services are the same. motor vac (by snap on) is the best i have seen, and generally take the longest to perform.

drivinfaster