m20 stumbles/hesitates during acceleration

[dyasko]

Hey r3v,

My 325i has been developing an issue where it will stumble pretty badly above the 2k mark while accelerating. It did this a couple times about 3 months ago and then didn't do it again until yesterday, so I more or less forgot about it. Based on my searching, it sounds like it could be the c191 connector, fuel pump, fuel pump relay, afm, or tps. The c191 seems like the most likely culprit to me, but one common theme of this problem is that it almost always happens after I rev the motor up around 4k or so, which makes it sound like more of a fuel pump issue. Anybody had this problem before? And what ended up being the culprit?

[itsonlygeorge]

check o2 sensor.

[EatsHondas]

My money is on weak fuel pressure, worn out ignition components, or a dying crank position sensor.

[Mwishlist]

So I had an issue with the C191 connector. Super simple test, start the car and while idling reach down and wiggle the C191, if you get the stumble it may not be your only problem but it's definitely a problem.

I had this totally random 1 second loss of power that I couldn't track down. It would usually happen when I would accelerate but would only happen like once every two or three weeks. A few weeks ago the car suddenly started acting like it was out of gas and died in a parking lot. Crank forever but wouldn't start. I thought is was my fuel pump but it had spark and fuel? I started jiggling connectors and it fired right up. Once I had it idling I would touch the C191 and it would stumble and die. The PO hadn't put the C191 connector back correctly and it was loose. Luckily I didn't have to rewire, just tighten.

[dyasko]

Thanks everybody for the suggestions. I'll try all of these things and see what works

[dyasko]

Looks like the cps wire rubbing against the fan pulley was the problem


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