Flashing CEL...more problems

[RoadRage]

So I'm driving back into the city after a round of golf on Monday, and out of nowhere the car starts vibrating horribly. It felt like the engine is gasping for air and is about to shut down, or explode. Then the flashing CEL comes on, and I know somethings F@cked.

I'm pretty sure it's a bad o2 sensor, but can someone confirm this for me. I don't have vag-com. At idle, the car vibrates a ton. In 1st, trying to get rolling it struggles badly, but as I gradually get up to speed it kind of smooths out. If I'm up to speed and take my foot of the gas the car is smooth and feels like nothing is wrong.

Second problem:
For the past couple of weeks there has been a weird noise coming from the engine bay immediately after startup. The problem, other than the noise, is that it's inconsistent. I thought maybe it was only on cold starts, or warm starts, but that isn't the case. It just happens sometimes, or it doesn't.

It sounds like a whining/whirring noise right after I let go of the key. I asked a friend to describe the noise and he said it sounded like a horse neighing, and it kind of does. It's like a mechanical horse letting out a scream for help. Any ideas on what could be causing this noise?

TIA

[Nebone]

The first problem sounds like you have a vacuum leak and its misfiring. Check vacuum lines around the intake manifold.

[A4Shizzle]

First part sounds like a textbook misfire. Can't imagine what that noise is though, they may be totally unrelated. I'd just put new plugs in after gapping each one preperly. It'd only cost like $10 and you can post pics of the old ones after.

[2K1Ultrasport]

most likely a misfire.
scan to see which cylinders are going.
usually a coilpack gone bad.

as for the noise, you sure it isnt just your secondary air system?
it doesnt always only come on for cold starts.

[RoadRage]

I did do a brief look for any disconnected hoses right after it happened. I didn't notice anything, but I'll check again.

The spark plugs only have about 4k miles on them. Could they be dead at that age? Could it be coil pack?

[t1demont1]

It could be a coil pack, but it sounds more like a vaccum leak. The second one might be your diverter valve going out. Its hard to tell without a sound clip.

[seank]

Since the CEL is flashing it is definitely a misfire. Since you have an AEB I would first suggest checking the ICM which is located on top of your airbox it has 2 plugs going into it, it is most likely definitely this if the misfire is in cylinder 2. You can check which cylinder is misfiring without vagcom by disconnecting each coil pack one at a time, if the misfire stops when you disconnect a certain coil, you found the cylinder of interest.

[RoadRage]

Alright so I looked harder for disconnected hoses. Still haven't found anything. Maybe it's not disconnected just torn.

I also unplugged each one of these one at a time, and then started the car up. There was no difference. It either felt/sounded the same, or was worse.


Here is some video/audio of the car at startup. You can easily hear the squeal after it fires up. Any ideas?


Thanks for all the help/tips so far.

[vegaspassat]

I didn't hear any mechanical horse, but it sounded like maybe your starter wasn't disengaging right away. As for the mis fire do what seank said. When you unplug a cylinder and it makes no difference in the way the engine runs, then that is the cyl with a misfire. Your best bet would be to go and get the car scanned. I've heard that places like auto zone will do it for free.


~D

[AE Performance]

I think you have a coilpack issue... Leave the car running... and pull up each coil pack one at a time, dont disconnect it. If the car doesnt idle any worse by pulling a certain one out (or could even be more than one) then you've found the culprit. (because its not doing anything) Replace it, and you'll be back to normal.