BMW Misfire/ Rough Idle M54 6 Cylinder Low Compression
Does your M54 BMW engine have a misfire/ low compression ? Don't be quick to replace the engine. Please try this first before that is done. Could save you $1000's !!! Please Read Below !!! How this is done: Remove the Coil then the spark plug. After they are ALL out, we pour 1 ounce of fluid into each cylinder. Then I reinstall the spark plugs and let the car sit overnight. The next day you want to remove all the spark plugs again. Place a heavy towel over the valve cover so that all the spark plugs holes are covered. Proceed to crank the motor over using the key. Do this 4 separate times for 10 secs each time. Reinstall all the spark plugs and torque to spec. Reinstall all the coils and connect harness. If you were planning to replace the spark plugs ( Which I recommend ) I would wait till all the cleaning chemical is burned out of the cylinder. Start the car and vary the rpm for 1 minute between 1000 RPM and 3500 Rpm. if the engine seems like it is not clearing out or running rough after the 1 minute. Turn the engine off and restart. After the 1 minute has been completed, then run the engine @ 3500 rpm for 5 minutes ( Pending that there are no other issues with the engine) After that an extensive test drive on the freeway is recommended ( 15-20 miles). This chemical is strong and not healthy to breath so lots of outdoor space and fans to blow the Exhaust fumes away is recommended. After all is completed then reinstall the cover over valve cover. Depending on the mileage and time car has been driven in this state, it could take multiple tries to resolve issue. Also it is good to have car diagnosed as a low compression issue before performing this repair, since many other issues can mimic this symptom. Hope this helps!!
Misfire Faults and Umetered Air Leaks BMW 3 Series, X3, X5 with M54 engine
This situation could be on any BMW with an unmetered air leak with the M54 engine. This would be the 6 cylinder engine. The vehicle can run rough and misfire.
BMW Common Air Leak Locations M52TU M54 Mixture Too Lean
BMW Common Air Leak Locations on an M52TU or M54 engine. This would apply to many models like the E46 3 series, E39 5 Series, X3 E83, and X5 E53.