e39 528i Sport 5M - off-idle "bucking" in 1st gear

[Tim in N FL]

Hello Bimmer.Info 5er owners,

This is my first post to this forum. Sorry if my post is afield here...understand this is primarily an e34-focused forum :)

I've owned my titansilber 1999 e39 528i sport-premium 5M since March '04. Would appreciate your thoughts on this issue. Since I purchased the car, I've experienced two annoying drivability issues:
1) "missing" / "misfire" caused by 2 faulty spark plug connectors (replaced) and;
2) when my car's engine is on the cool side, I experience only what I can descripe as "jerkiness" or "bucking" with light throttle input as I leave my my driveway and begin driving through my neighborhood at little more than an crawl. I'm NOT lugging the engine.

I'm wondering what this could be:
1) an ignition system issue -
2) Dual VANOS system issue (M52tu engine) -
3) clutch pressure plate wear? My tech told me that the PO must have overheated the clutch at some point. Perhaps he was the type to rock the clutch at stoplights and on hills?

I would appreciate any thoughts / ideas the group members could offer. If you have any questions of me, please fire away.

Thanks in advance.

Cheers,
Tim in N FL

[AllanS]

I've heard that that type of bucking off idle is due to the way the previous owner rode the clutch... harder, quick shifts are supposed to cause that. I sort-of have this problem, but it's not as bad as yours I don't think. Supposedly there's nothing you can do about it's grabbiness, short of a new clutch.

[Tim in N FL]

AllanS,
Many thanks for your comments on my 528iS' "bucking issue". The PO was an older gentleman and this was his "mountain home" car in Asheville, NC. Evidently, he traded the car in on a new Mercedes...wtf? I got it from a wholeseller, ostensibly for a very good price. I wonder what a clutch job runs on this model? My guess is $700-1000 parts and labor. NO rush right now....just annoying and embarrassing at times when the bucking and jerking begins. Interesting to note that high humidy (rainy days) make the problem worse...perhaps the pressure plate is stickier/grabby under those conditions?
Best,
Tim

[632 Regal]

I would look into the "cooshy" items such as motor/trans mounts, the guibos and center support if applicable on that car. Aside of the clutch and possible fuel management issues as suggested there isn't much else to it.

Good luck!

[Tim in N FL]

Jeff B (632 Regal),
Thanks for your thoughts / ideas. Everything you mentioned was on my "rule-out list" with the exception the motor / trans mounts. I'll follow-up on this thread as I make progress chasing this down.
Best,
Tim

ps.
Godspeed to anyone in the path of Hurricane Ivan...looks like a really bad one. Be safe!

[Julius]

I must say mine has a bit but not as much as yours. Sometimes i just take off in 2nd instead cause its easier and one less gear to change. Your 528 should have enough to take off with no trouble in 2nd aswell since i can do it on a small hill.

[Bellicose Right Winger]

Does this jerkiness/bucking occur only during clutch engagement or does it occur when your foot is entirely off the clutch pedal? What is mileage on car?

Paul Shovestul




Jeff B (632 Regal),
Thanks for your thoughts / ideas. Everything you mentioned was on my "rule-out list" with the exception the motor / trans mounts. I'll follow-up on this thread as I make progress chasing this down.
Best,
Tim

ps.
Godspeed to anyone in the path of Hurricane Ivan...looks like a really bad one. Be safe!