Q: Stalling and misfiring at idle on a 1999 BMW Z3

asked by on April 13, 2016

I have a BMW Z3, 1999. At idle, it sputters a bit and feels like it's going to stall but just as it bangs on, it first feels like a misfire. The car drives fine when it's warm, and idles under 1,000 RPM.

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Those things are notorious for getting vacuum leaks on them because the tops of the engines are all made out of plastic--including the intake system. Especially on the driver’s side, there are all kinds of plastic piping. You’d want to look for the vacuum leaks first and if you’ve got a vacuum leak it’s going to do all that stuff. Now, if you don’t have a vacuum leak, those are also notorious for having very bad MAF sensors. Mass air flow sensors--check that with a scan tool too. But, it’s often vacuum leaks on that car. It’s really typical when it gets that old. I would have a certified mechanic, such as one from YourMechanic, inspect your vehicle’s misfiring and stalling issue so that you know exactly what should be repaired.

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