Vibration when I accelerate

[Greg]

Ok Guys. I have a 2001 4.4 with 95K miles. Recently I noticed when I accelerate I get a vibration under my feet. I am assuming it's probably a exhaust leak. Anyone have any suggestions?

[x52003]

this because of the cylinders coyals not the cylinder it self

it will be one of the koyals damage

but to check it you have to know it by computer programing.

that all

don't let any body sheet you

[jst2878]

Front suspension components is crapped. Have an experienced BMW mechanic isolate the problem

[Weasel]

If it is a misfire caused by coils then the check engine light would be on, and flashing during the active misfire. If it is the front suspension you should also feel it at other times, possibly under braking as well. I've even seen this problem from a broken motor mount. Basically, need someone experienced to diagnose as it could be one of many things and you don't want to guess by throwing parts at it... that costs more than proper diagnosis most of the time.

[m5james]

Originally Posted by Weasel

If it is a misfire caused by coils then the check engine light would be on, and flashing during the active misfire. If it is the front suspension you should also feel it at other times, possibly under braking as well. I've even seen this problem from a broken motor mount. Basically, need someone experienced to diagnose as it could be one of many things and you don't want to guess by throwing parts at it... that costs more than proper diagnosis most of the time.

[Greg]

It's not the suspension. Had the entire front suspension replaced, very smooth ride. The SES light is on, but that's because of a Leak in the EVAP Emission Control System working on that also. This vibration is coming right under the accelerator pedal. I thought it might be a exhaust leak.

[m5james]

Originally Posted by Greg

It's not the suspension. Had the entire front suspension replaced, very smooth ride. The SES light is on, but that's because of a Leak in the EVAP Emission Control System working on that also. This vibration is coming right under the accelerator pedal. I thought it might be a exhaust leak.

You said you think it's an exhaust leak twice now. Exhaust leaks make a distinct knocking sound, so unless you've got broken engine mounts from jumping your X while offroading, I HIGHLY doubt that's your problem. Of all the years I've been working on BMW's, I've only had one exhaust leak which was my own fault from not tighten a single bolt at the collector after a clutch replacement.

The flex disk (guibo) is a big rubber donut that is bolted between the driveline halves. It would be far easier to check if you can get the rig in the air, having someone running though the gears and see if things are moving around and causing this vibration. They detoriorate and chunks break away, leaving only the 6 bolts holding it together. I've seen people put this off long enough that the driveline was slapping around inside the tunnel and you could feel it all over the floor. Is there a hard clunk when going from forwards or reverse while sitting still?

What is going on w/ your emissions system?

[jst2878]

Def take weasels advice, he is a guru of e53s. And if it's not the motormount make sure to check the flex disc on the front driveshaft.

[prwdmd]

I've had a vibration on acceleration. Take a look at my thread from a few months ago. Flex disc was my main suspicion, but it turned out to be a bad half axle. This was diagnosed by the dealer. Completely took care of the issue.

A vacuum leak will give you a rough idle or vibration while stopped at a light for example, but it wouldn't be noticeable enough to shake the whole car while in the highway. That is more indicative of a drivetrain issue.

[Greg]

I'll check the motor mount. I've had both front axles replaced along with everything else that has to do with the front suspension. I'll post after I have it checked. Thanks