Hey guys i feel like my bmw 550i is losing power and at the same time
Im wasting more gass?? My dad has an e70 x5 4.8l
Which is the same engine and its much better on gas
Then my car?

 

maybe you need a fuel injector cleaning

 

Or new injectors all together.
The injectors are a weak point on the n54 TT engines, but I'm not sure if they are or not on the v8s. How much worse is the gas mileage on your 550 than on the x5?
My 535i gets worse gas mileage than my 335i because the intake valves have a lot of carbon buildup on the 535 - however, dirty intake vales are only an issue with Direct Injected cars, and your 550 does not have DI.

 

BMW's like to be beat, you pussy foot around they hate it and will act up. example, i didn't drive car much ( drive my motorcycle daily) for a few months only to bring kids to and from ball games so no betaing it with them in car even thought they like it. car when starting would be realy wough for like first 10 seconds after cold start (never during warm or short layovers). sold myself was plugs (96k it was time to do anyhow) so i changed them...same issue. then figured it was fuel filter, didn't have time to do it but that's was next logical thing. i had to go to FL to see my mom drove 350 milesish down and on way back had some pontiact g8 gt trying to play so we beat our cars for about 40 mins driving anything from 80-90 cruising to roll ons to 140ish (FYI they are weak on highway and he took his medicine everytime). okay home now and car has yet to cold start rough since i have been back, i live in Florence SC and do more short/city driving and never go on highway much so just goes to prove they like to be beat....also gas milage has now picked back up!

even service managers will say beat them or they will act up!

 

+1. BMW's need to be driven like the "Ultimate Driving Machine"! That's their slogan for a reason - they're not building cars for Grandma's or people with bad backs (even though they're ridiculously comfortable compared to other performance cars).
However, I would argue that BMW's are not "weak" on the highway, but rather that is where they excel. The n54 TT is virtually unstoppable 60-130!

 

Try changing the spark plugs, air filter pour some fuel injector cleaner into the tank on your next fill up. Either Chevron Techron - avoid the 3-5 bucks bottle from walmart or gas stations. Or BG44K , order online.

Do a basic tune up and see if it helps, if not then take your car to an Indy shop and have them diagnose the issue.

 

first check tire pressures
then do some basic stuff like plugs air filter etc.
clean the maf sensor
try some fuel injector cleaner too.

and there is truth to driving it hard. the heat from driving hard helps clean out carbon buildup in an engine and exhaust o2 sensors etc.

 

I would suggest that you take a look at the condition of the Air filter condition and more importantly, check the Mass Airflow sensor. If it is dirty it can drastically impair MPG performance.

Be careful. The Mass Air sensor is about $500.00 and is very delicate.

Also, I just drove my 545 about 1400 miles at speeds of 70 to 80 MPH. Now I am concerned about hitting the throttle hard fearing that I might be thrown in to the back seat.

 

Lol thanks for your response guys i will look in to
Doing a tune up sometime this week.