Trying to figure out if this is a timing issue. Wife reported rough idling, I think it's more of a vibration. No missing at all. Almost as if one of the fan blades are missing or something. It's a low vibration, nothing violent.

She also said it's louder. I confirmed that during acceleration, it does sound like a MUCH bigger engine. Almost like it's working too hard to get up to speed. Sort of a whooshing or whining.

My first thoughts are a slipped timing belt. What say you?

BTW, this is a 99 528i Sport, 201k on the car, about 99k on the engine.

Bump

The engine has a timing chain, not a belt, and the chances of it having jumped a tooth are extremely low

The problem description makes me think of an intake leak and resultant partial misfires or a problem with the CPS. The whoosing noise might be from a bad fan clutch or it might be from an intake leak. You'd want to make sure that the fan clutch is good since the fan won't take too much time at high rpm w/o exploding.

Yeah, chain. Didnt mean the belt. One of the two chains.

Intake leak, eh? I'll check the fan more closely and take a good look at the fan clutch. Hopefully it's just an issue with the fan like a broken blade or something. I considered an intake leak but the fact that it's not missing at all makes me thing of something more mechanical. While it's idling, I go to the exhaust and there is absolutely no sputtering or missing at all. Perhaps it's just time to change the clutch and fan to be safe anyway.

Thanks for the tips.

Fan clutch. Took a good look at it with a flashlight. Fan doesnt spin freely when cold either. You can see where the little spring is trying to come out.

Ordered a new one from Ebay.

Thanks for the tips thejlevie