Need help fast!!!!!!!!

Hello All,

I'm new the Bimmerfest forums and in dire need of help. I am the proud owner of a 2002 BMW 745i located in Houston, TX. About 6 months ago I took my car to BMW to have the transmission check and after they completed the diagnoses I was told that they would need to replace the transmission pan, lower oil pan, spark plugs, ignition coils 1,6, and 8 and the alternator bracket gasket. I've recently had all of the work completed with the exception of the alternator bracket gasket a an independent shop based on BMW's findings. The problem that I am have is with all of the work that has been completed my car still runs horrible. The ride is rough and it runs loud and appears to be misfiring. The shop owner check the codes and it stated that the coils 6 and 8 are not getting enough fire so the shop owner suggested that we change the mass airflow sensor which did absolutely nothing. I've also had the battery replaced and as well as having the oil and filter changed at the same shop. I also taken my car to another mechanic shop for a diagnoses and explained everything that has already been done only to hear them say they would have to repair symptoms to eventually find the actual problem which could run up a rather large repair bill. I've spent a great deal of money for my car to still run like crap!
I know I've given a lot of information but does anyone have any suggestion?