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Posted by: Bob2003
Question I have a 03 500I it has run great up to now. I have about 1400 miles on it Problem is it runs good at low speeds but when I get on it around 30 MPH + it starts to lose power and sometimes backfires. I have change the plugs and airfilter but does the same thing has anyone had this problem or no what may fix it.
Thanks.....Bob
Posted by: Bob2003
Everything is standard nothing added. I change the plug and clean the filter still same problem. I will be taking it to the dealer tomorrow to have the valves/timing adjusted. I will post results when I get it back.
Posted by: 1wook
Did you change the exhaust any? Backfiring is a lean symptom.
Posted by: Bear4570
Either an exhaust change or dirt in the carb causing a partially blocked jet causing the lean condition.
Posted by: weez440
chances are i would agree with bear sounds like just a simple carb cleaning would do the trick. they are very easy to clean but if you are unsure i would find someone that is or take it to the dealership.
Posted by: CrashinIt
maybe your belt is worn. But that would not cause backfire's.
