Strange Vibration at ~4000 RPM

[m3f_romh]

1998 M3 Coupe.



I have talked to one of the BMW technicians (a friend of mine) over the phone about my problem and he has never heard of it. Here it goes. I feel a vibration under my feet and in the 5 speed shifter. This happens when when I am de-celerating in 2nd, 3rd, 4th or 5th gear! This is the exact description of the situation.----

Let's say that I am acceleating in 2nd gear(could be 3rd, 4th or 5th) up until 5000 rpm, when for some reason I need to stop accelerating and therefore I let off the accelerator but with the gear still in place. I do not touch the clutch yet! Obviously, the car will start to slow down and the revs will start coming down. When the car is decelerating at about 4000 rpm, I feel a very noticable vibration in the shifter and under my feet, for a good 2 or 3 seconds. Its very annoying. Its almost as if I were going over little bumps on the road. Kind of like the ones on the shoulders of the highways to remind you that you're swirving off the lane. Of course, the vibration is not that severe, but still noticable to the everyday driver. This doesn't happen all the time. I would say that 40% of the times.

Well, the big question. Has anybody ever experienced this?



1998 M3 Coupe.

100% stock, but I drive it very hard.

[m3f_finespline]

Vibrations are frustraiting and difficult to identify and fix. I can't say I know exactly what you have, but some general advice from experience on my Z28 convertible. The undercarrige x-brace was pushed up against the exhaust pipe. Bending it back was the fix. Long story made short - stay away from "Merchants Auto" and single point lift racks



Vibrations I have personnaly experienced: mud on the inside of wheels; giant tar ball stuck on tire, out of balance drive shaft ,worn driveshaft spline (it's not the drive shaft if the vibration is always at the same RPM when in different gears), bad cv joint on IRS.



Start trouble shooting with the cheapest (to fix) things first and don't replace it until you know it's broken.

[m3f_romh]

Thanks alot finespline. The drive shaft had come up as one of the suggestions from the BMW mechanic. But he was quick to point out the fact that he has never in his 10 years of experience at BMW replaced an M3's driveshaft.

I bought my M3 with only 10,000 miles in 1999. Now it has 103k.

Great reliable car. It has had some problems but nothing that has left me stranded. Well, actually one (the fan clutch at 80k). I've replaced the ac and alternator belts twice. Each at 50,000 mile intervals on the dot. A week ago, I replaced the spark plugs and they were still in very good shape. The oxygen sensors were replaced at ~ 70k under the CPO at no charge (Only the $50 deductible which I didn;t agree with.) My harmon kardon speakers have blown twice. That's due to maxing them out all the time.

Anyway, I was going to trade the car in last July for an E46 330ci with 30k miles on it. I enjoyed driving that car. It was my sister's car and she treated it like a little kid. As smooth as the E46 was, it lacked the handling, power and sound of an E36 M. I couldn;t give mine up (even with 90k miles on it).

Additionally, my BMW mechanic friend told me that E36 M's are extremely reliable and he hardly sees them at the shop with problems. Just routine maintenance - its also probably due to the fact that they're out of warranty by now.





Thanks again.