Root cause of multiple OBDII codes???

[mackm]

I have an 02 325i that my wife drives daily. This morning, she left to run an errand and called me to say the car was turning 4K RPM and only doing around 40MPH. There was an "exclamation point" showing near the "D" for "Drive" indicator on the dash. I told her to take the car back home and drive something else. I took the car later in the day to a tranny shop (thinking the tranny was slipping) and he read the tranny codes - which there were none! However, there were MULTIPLE codes on the OBD II read (although the CEL was not lit) for "Misfire Cylinder 1,2,3 and 5" "Secondary Air Flow Low # 1 and #2", and an "Electronic Thermostat Control" code. When I drove the car to and from the tranny shop, it ran just fine - no issues.

The only notable issues with the car in the past few months have been a rough idle when it was cold in the morning (hard to start 1 time about 2 weeks ago with this issue), but when it warms up and you restart it - it does fine, 3rd gear "hangs" longer than others when the car is cold until it has been driven a bit and warms up, and the vent blower inside blows bursts of air when first started until warmed up (and it makes a whining sound under the hood like the hard drive on a computer then too, but shuts down once warm) and it blows consistently. Appears all of these issues are when the car is cold.

Does anyone know of a singular root cause that would be the culprit to all these other issues?

[FCPGroton]

It sounds like an ignition issue. How old are your spark plugs? If they are old, it may be time to replace them. Otherwise, then next thing I would look at are the coil packs. More then likely they are on there way out.

[mackm]

Bought the car with 50K on it, and it had just been completely serviced including tune up, any recalls, etc. It just turned 100K - so it likely is time. It's planned for a tune up after New Years already with my local mechanic. He is perplexed with this issue. I have read several threads on this site with very similar problems. Some of them point to a Secondary Air pump issue, CVV or MAF - but I can't find a direction to start. Even more strange is the fact that the codes were not cleared off yesterday when it was scanned, but it was rescanned today, and there are NO CODES??

Really at a loss here. Car has run fine since this issue yesterday morning.

The mechanic was at a further loss today when we started the car (while scanning codes) and when he shut it off, there was this "release of air" sound about 5-10 sec's after shutdown that caught his attention. So I jumped in while he was nosing around under the hood trying to isolate the sound after multiple start ups and shut downs. He ultimately put his hand into the air box to see what it felt like when I shut down. Oddly, after shut down and the 5-10 sec's, it still "sucks" air through their air box? How could that be? The engine has to run to create vaccum?!?!?!?!?