Hey guys.
2001 325CI - 60k miles. Changed oil at 50k miles. No other modifications or upgrades have been done.

Recently, I've noticed (and everyone has noticed) that my car has been sounding like crap. It actually sounds like a 1985 bronco to be exact. Some say it sounds like a mac truck.

symptoms :

A. Sometimes the RMP pin jumps from 0-2 or 0-3 while the car is idle - it sounds like the car is going to die, so I give it some gas, and its fine. Sometimes I give it some gas, and when the pin goes back to primary position, it jumps some more, and then the car just dies.

B. I am getting a chuga chuga chuga sound from the engine. That's what my friends mean when they say it sounds like a mack truck. I at first thought it was the belt perhaps, maybe it was dry or cracking...but that wasnt the case. I used wd40 to lube up the belt and it still made the noise.

I put my ear next to the radiator and the sound seems to be coming from there, it might be my fan - possibly loose or part missing. I'm hoping the issue isnt engine related and its simply something out of place or loose. Never got into accident so it wouldnt be anything damaged.

i will try to record the sound for you all if you need it.

I would bring it to BMW to get looked at, but i know they will charge me 150 for a diagnostic, which is BS.

Could that sound mean low or dirty oil? I put about 2 quarts of oil this morning 5w30 synt - wondering if maybe it was low. 2 quarts brought it to avg. level, but it definitely could have taken a 3rd quart.

Coming from very little experience, i really have no idea what it could be. All i can say are the symptoms above. Any help would be great.

Here are a few notes.

I dont use "super" gas all the time, maybe once a week. I usually put in Plus.

I should note that the car has shut off on me while coasting to a red light or stop sign. I don't mean stalling - I mean the car was in neutral - and due to the RPM's jumping (as noted above), the car would shut off while i was driving. I then would coast to a stop, and start the car again and it would be fine for few a few days (not sure if this is related to the engine/hood noise of chuga chuga chuga)

It's a manual (stick)

18" aftermarket rims

No modifications to air filter, intake, exhaust, or engine components.

I change the oil myself about every 10k miles.

Garage kept, 1 owner (me).

I really would love some thoughts about this or some insight guys/gals. Thanks so much in advance.

There are a number of things that could cause this (intake leak, failing CCV, flaky CPS, bad MAF, etc). Nothing in the description points to an obvious cause, which suggests that diagnosis by a BMW tech is probably the best course of action.

+1. 150 is about an hour of dealer diagnostic time in this area. If that's too much find a good indie BMW shop. But that 150 will seem cheap if something goes severely (and expensively) wrong.