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Discussion Starter #1
Ok well i know there has been a million threads about po171 po174 but I cant seem to find my answer. I drive a 2001 bmw 330ci. Replaced Valve cover Gasket , spark plugs, Both intake tubes, all of my little vaccum hoses, replaced disa gasket, ofhg gasket, air filter. 2 things i havent done are clean the MAF even though I know mines is good and clean the ICV. Other than the car throwing the codes po171 po174 when the engine gets warm whenever i shift from park to reverse or neutral to drive the rpms drop to 500 and rises back up to around 600 and it vibrates the dash. While its in park or neutral it sits silky smooth around 750 rpms. I have gone through a bunch of threads with people with the same issue and no one seems to have a cure or if they did find one didnt post it. Also when im coming to a stoplight the rpms drop and raise like i was explaining. Would a dirty ICV really make it do this? Or am I have other issues I dont know about.
 

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Discussion Starter #3
https://youtu.be/g0OCwJEVJFg

Theres a Video to be more clear. Thats when the AC is off when the AC is on it still stumbles just less.
 

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Post warm idle Fuel Trim values and Freeze Frame data.

Yes, power brake boosters are failing at a pretty rapid rate after about year 12 on these cars.

Lean codes could be due to anything from vacuum leaks, crankcase air leaks, power brake booster or even a bad/Asian counterfeit MAF.

Without warm idle Fuel Trim and Freeze Frame data, it is all a blind guess, even with the data it is a wild ass guess because we cannot put out hands on the car.

Suggest you read my comments in this thread - http://forum.e46fanatics.com/showthread.php?p=16727145
 

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had this code twice so far. First was one of the small vacuum lines coming off the secondary air pump had a crack. Second time was when I cracked the valve cover putting it back on after a gasket change. This one was found with a smoke test at the shop.

Good luck!
 

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Discussion Starter #8
Post warm idle Fuel Trim values and Freeze Frame data.

Yes, power brake boosters are failing at a pretty rapid rate after about year 12 on these cars.

Lean codes could be due to anything from vacuum leaks, crankcase air leaks, power brake booster or even a bad/Asian counterfeit MAF.

Without warm idle Fuel Trim and Freeze Frame data, it is all a blind guess, even with the data it is a wild ass guess because we cannot put out hands on the car.

Suggest you read my comments in this thread - http://forum.e46fanatics.com/showthread.php?p=16727145
Ill post those as soon as i can
 
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