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      08-03-2018, 11:14 AM   #12
desertman123
E82 Mudflap Ambassador
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Drives: '08 128i
Join Date: May 2016
Location: Orlando, FL

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Garage List
1992 Honda Beat  [9.50]
2008 BMW 128i  [10.00]
2014 BMW 528i  [10.00]
Quote:
Originally Posted by drunkenup View Post
Since the rebuild the really worst of the lift-off jerk disappeared, but throttle tip-in and lift still causes a minor jerk. Occasionally it jerks more violently. Thought it might be bad motor mounts, vacuum leak (maybe the breather hose), but my doubts are growing on the DISA.
I have a brand new breather hose and motor mounts within the last ~10k mi. Not sure if we're describing the same exact thing. For me the jerking happens at low speeds, like if I give it a bit too much throttle after the clutch engages it'll CHUG-uh-CHUG-uh unless I immediately pull off.

Do you have a manual trans? I began thinking my jerking was from a DMFW getting quite worn - but with your input it might be that the DISAs failing, or maybe a combination of all the above.

And I've always suspected a vacuum leak. My idle once fully warmed up occasionally feels a little rough/vibrates- the RPMs don't move at all, but it feels like I have the AC on. I don't know exactly how smooth this car is supposed to be, but it would be an explanation for these small symptoms. Fuel mileage is good and so is performance, but who knows.

The motor hisses a little bit - I know these things make all sorts of odd noises but the hissing can be a bit loud. This is what prompted me to replace the breather hose. I tried a real quick at home smoke test but didn't see anything. When I did my valve cover gasket one of the little breather things broke off so I reglued it, maybe that's it? Who knows, I'll check it out when I have time or whenever I do the MILVs.
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My 2008 128i - Sparkling Graphite/Beige - Sport pkg - 6MT - Click me!
Parents' 2014 528i - Mineral White/Ivory White - fully loaded
Instagram @Andreys_128i and @Honda.Bito
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