97 328i stumbles, sometimes no power - help
1997 BMW 328i 220k miles, starts up great and runs ok when not under strain, when u get on the gas at low rpm the engine flattens out = no power, it sometimes backfires. CEL comes on, codes say oxygen sensors but I recently put universal O2 sensors in.. Spark plugs and coils and fuel filter are new also.
Any advice would be appreciated