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Stuttering, hiccup at low RPM??

Discussion in 'E39 (1997-2003)' started by 190796, Nov 16, 2008.

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    190796

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    My 528i 1999 manual trans engine has developed a stutter (feels like spark is cutting out) at low rpm. As soon as I coax it to about 2,000 rpm it pulls smoothly all the way up. If I shift such that I drop into the next higher gear above 2,000 rpm everything is normal. If I try to access the low rpm torque it bucks and stutters.No check engine light. Does it cold or warm.

    Ideas? Thanks, Scott Graham Mpls, MN
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    mooseheadm5

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    Sounds like it could be an air leak or a need for plugs. How many miles and how many miles since the last service?
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    190796

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    111,500 miles and I do not know the answer to how long since the last service because I bought it 7500 miles ago. It was recently hooked to a "real" diagnostic computer at a service center and there were no codes, etc... I have 2 green bars on the service indicator when I start it up. Would an air leak only be evident at low rpm? Plugs seems like an easy first step. I was actually thinking that.
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    mooseheadm5

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    An air leak would be evident at low RPM. The plugs are not usually changed until 100k or so, so that would be the first thing I would do. Buy the correct ones as specified by BMW and you will not regret it. You may find cheaper ones in another brand, but the results may be good or bad. Time for a general tune up. Ignore the green lights and switch to a mileage based schedule. Oil every 5-6k (synthetic is your best bet.) Air and fuel filter would be good, too. Check all your cooling system components, drive belts, change coolant and brake fluid, etc. If you can't do it yourself, it will cost you, but if you plan to keep it, you had better take care of it or it will get you for much more money on down the road.
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    190796

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    Thanks Paul. I just did all the belts and renewed some rubber parts when i bought the car. I run Castrol Fully Synthetic oil as did the previous owner for the entire life of the car and I am old school when it comes to oil changes. I remember doing my 2002 every 3000 miles so the 5000 I do now even seems long! I'll do the fluids and filters you recommend. I am due for new brakes, I've got the rotors and pads, just need to put in a Saturday. I'll probably have the fluid flushed professionally after that. So messy and with the right equipment so easy. I try to know my limitations.

    Thanks again for the tips about plugs and tune-ups. Scott
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    mooseheadm5

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    You may also want new plug boots, especially if you find yours are oil fouled from a leaking valve cover gasket.
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    190796

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    Thanks for the tips Paul. I changed the fuel filter, plus and plug ends and yep, nice silky smooth power across the entire rpm range. thanks.

    Now, how about a sticky throttle? Sorry to take advantage of your expertise.

    Scott Graham

    Buckeye653 guest

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    You might want to check the throttle body. Sometimes there's carbon buildup around the buttterfly valve, particularly at higher mileage. While you're in there get some CRC MAF cleaner and clean the MAF. CRC makes throttle body cleaner also.

    I have the M52TU (dual VANOS) engine and the rubber intake boot has a small elbow underneath just before the throttle body. If you remove this boot check the elbow for cracks. This creates an air leak which usually results is a whistling sound below 2,000 rpm. The severe angle on the elbow and heat contribute to failure. No driveability problems however. I drove mine for about 40,000 miles before I figured it out and replaced the boot.

    If you have strange idle problems, particularly in cold weather upon startup, it could be the VANOS. The seals go bad. Cheap and simple fix.

    George S.
    Columbus, OH
    2000 528iA Sport
    1982 633 CSi
    1991 325i

    ViolinARC guest

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    Clean your MAF...

    +1 on the VANOS and here is a link to a thread I posted regarding the MAF cleaning: http://forums.bimmerforums.com/forum/showthread.php?t=833346

    GL...

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