Keeps stalling 2-3 times pops in the intake, possible bad MAF?

BHAMDOC1973

MEMBER
2003 BMW 325I
6 CYL
2WD
AUTOMATIC
170,000 MILES

I bought this car running rough at cold start, so bad that it keeps stalling 2-3 times before it can stay running while misfiring and feels like there is back pressure because there are pops in the intake. I thought the secondary air may be the issue but based on readings many say MAF could be the issue. So, I unplugged it before a cold start and the issue is almost completely gone. Is it possible the MAF is bad then?

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,913 POSTS

This sounds like a major engine problem to me, which will give strange MAF sensor readings. I would start with a compressor test which this guide can help with:

https://www.2carpros.com/articles/how-to-test-engine-compression

Please get back to me with the readings.

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Thursday, April 11th, 2024 AT 11:24 AM

BHAMDOC1973

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1,291 POSTS

Major? The car drives excellent once the MAF is u plugged. I gave no symptoms of anything major, no overheating, no check engine light codes. Once it's unplugged there is no problem driving the car, no misfires, compression is out of the question.

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Thursday, April 11th, 2024 AT 11:40 AM

KEN L

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42,913 POSTS

Popping through the intake? Can you upload a video? I cannot see what's going on this is why I ask for videos. Try replacing the MAF sensor to see what happens. Check out the images (below). Let us know what you find.

Image (Click to make bigger)