[SfValley335i]

I got a 6mt 135i n54 with only 30k miles. I'm FBO... The car drives fine power wise, there is no vibration or noise inside the cabin on hard acceleration in 1st or 2nd gear.

However, under hard acceleration in 3rd gear or higher 60mph+ , the car has this annoying vibration, it doesnt shake the car but sounds like a car with really stiff engine mounts... Sounds like "Vrrrrrrrrrrrr"

The car shifts and accelerates fine, I'm clueless at what could be wrong or what to look for.

Im out of warranty so I do not want to pay the dealer a visit...

Any ideas on what to check would be appreciated.

[Dave W.]

Did you do any work on the car recently?
Can you tell where the sound is coming from? Front, rear, center?
Since the sound is related to speed and torque, I'm guessing something went wrong with the driveshaft.

[SfValley335i]

Originally Posted by Dave W.

Did you do any work on the car recently?
Can you tell where the sound is coming from? Front, rear, center?
Since the sound is related to speed and torque, I'm guessing something went wrong with the driveshaft.

I had suspension changed last weekend, downpipe two weeks ago, spark plugs 3 weeks ago.


Hard to tell where sound is coming from, I'd say center or rear.

If cruising at 80mph theres no sound, but once its in boost accelerating hard, 4k rpm+ I'll hear it until I let off throttle.

[AK 335i]

maybe a misfire. you won't always get codes. could be a faulty coil pack. maybe the big ape that changed your plugs gapped them or put the cheap autolites in, if so that's prob the issue, need to get some Bosch or ngk

[SfValley335i]

Originally Posted by smi1gj

maybe a misfire. you won't always get codes. could be a faulty coil pack. maybe the big ape that changed your plugs gapped them or put the cheap autolites in, if so that's prob the issue, need to get some Bosch or ngk

That big ape would be me, I did the spark plugs, they were oem plugs... Doubt its a misfire because I would feel a change in power.

[AK 335i]

ok if they are oem it's prob not plugs. but I'll say that I had that vibration at the drag strip
and still ran roughly the same times and traps and didn't "feel" a power loss, yet we pulled plugs and one was bad lol

[SfValley335i]

Originally Posted by smi1gj

ok if they are oem it's prob not plugs. but I'll say that I had that vibration at the drag strip
and still ran roughly the same times and traps and didn't "feel" a power loss, yet we pulled plugs and one was bad lol

Im pretty sure I have a leaky injector because I noticed one of my plugs was black... I guess I will until something breaks, rather than just replacing parts.

[Dave W.]

Bad injectors are a common problem on these cars and will cause misfires. Can you datalog fuel trims? Bank1 vs bank2 trims should show if there's a problem. If you 're still not sure I'd recommend either take it to a local BMW specialty shop such as LTBMW for example, or go to a local BMW meet and have an experienced owner ride along with you to witness the vibration firsthand to get a more solid diagnosis before you start spending money and replacing parts.

[aph335i]

Originally Posted by SfValley335i

I got a 6mt 135i n54 with only 30k miles. I'm FBO... The car drives fine power wise, there is no vibration or noise inside the cabin on hard acceleration in 1st or 2nd gear.

However, under hard acceleration in 3rd gear or higher 60mph+ , the car has this annoying vibration, it doesnt shake the car but sounds like a car with really stiff engine mounts... Sounds like "Vrrrrrrrrrrrr"

The car shifts and accelerates fine, I'm clueless at what could be wrong or what to look for.

Im out of warranty so I do not want to pay the dealer a visit...

Any ideas on what to check would be appreciated.

Dude I have same exact problem. Its not bad enough to really bother me too much but I feel you on the issue.