BMW 4.6 is poor acceleration and hesitation

[TerminatorX5]

you need to pull the codes in order to narrow the issue...

firt things coming to mind, the engine is suffocating for air, or starving for fuel, or getting wind blown between the ears - vacuum leak...

start with air filter - make sure if it is good..

then go to MAF - check to see if it works - unplug it while engine is idling, if idle stumbles, and then recovers, the MAF is probably good, if idle remains the same, the MAF is a toast. keep in mind, the MAF problem can be intermittent

Check the rubber boot feeding air to the throttle for cracks and tears, it can introduce unaccounted air into the system

check the throttle body for gunk

those are simple things...

then, listen for whistle of a vacuum suction

test for vacuum loss as per many posts here...

test for fuel pressure

and don't rule out that there can be other coils that are shorting out to the chassis under greater load...


your best bet is to pull the codes using BMW specific software and NOT a generic code scanner...