QuestionThanks a lot for your willingness to help. My car is a 325i. What actually happens at 2500 rpm is that the car starts bucking. I can tell both by the sound at the exhaust and the power loss in the acceleration of the car. What I usually do to temporarily fix the problem is to drive the car as fast as possible in each speed. This would clear up "the motor's throat" and then the car will run smoothly even at 2500 rpm. The car as far as I can tell does not smoke.
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Followup To
Question -
Hello, My car's motor behaves weird (feels like some dirt obstructs gasoline flow) at about 2500 rpm at pretty much any speed. Below 2500 RPM the motor runs smoothly, but then once it is close to 2500 rpm (in second, third and fourth speeds) the motor sounds weird as if the gasoline flow was not continuous. Once I reach 3000 rpm, the motor runs beautiful at any speed again. I don't have any idea of what is causing this. Help is needed!!! thanks.
Answer -
Luis,
First off, I need to know if you have a 1988 325i or a 325e? That makes a big difference.
Also, be more specific about the symptoms. Does it buck/jump at all when it hits 2500rpm? Do you feel it, or do you just hear the engine? Does it smoke?
All of those things need to be answered before I can help.
Thanks,
Josh
AnswerLuis,
It could be a couple things, I would suspect the O2 sensor, throttle position switch, or possibly the Air flow meter.
Those are the only things that will cause symptoms like this (99% of the time anyways). I would actually scratch the 02 sensor, but it probably needs to be replaced if it hasn't been done lately (50k mile life span).
Check the afm and see if its the cause, and then I would try the throttle position switch (on bottom of throttle body)
Good luck,
Josh
