I was on the freeway today in my 03 tt quattro and my car started running extremely rough, making a loud rumble, shaking, and hesitating all at the same time. I got off the freeway ASAP just as the check engine light started flashing and limped the car to my home (it was really close).

Any idea what this could be?

I already had the timing belt done months ago and got the car back from the dealership because the turbo hose came loose just last week (also had them do the 60k service).

 

Search feature will reveal this, but you are new on the site, so:

A flashing CEL indicates a misfire on one or more cylinders (which is corroborated by the rough running and shaking). One or more plugs, coilpacks, or wires has gone south on you. You need to pull the codes from the car to find out which cylinder was misfiring, but in the meantime at your house you can inspect the plugs to see if any of them are visibly carboned or showing signs of detonation. You should not drive the car until the problem is fixed.

On your member profile page, you should update your location info so others know where you live - you may have local AF members around you who are willing to pitch in and help you fix the car. Also, if you have a laptop, to go www.ross-tech.com and download VagCom (the diagnostic software for our cars). On eBay, you can buy the interface cable to hook up your laptop to the OBD2 port on the car so you can scan and reset codes on the car. This will give you tremendous advantages in diagnosing further problems with your car.

When you pull the codes this time (drive to a parts store like Advance Auto if you must - if no one around you has VagCom - and have them scan the car - they'll do it for free, where a shop will charge you), you'll see codes such as P0300 (random misfire) as well as at least one code such as P0301 (cylinder 1 misfire), P0302 (cylinder 2 misfire), and/or others such as that. Those will show you which cylinder(s) had the misfire.

Good luck with it and get it fixed ASAP - it's not a good idea to drive while misfiring - it's bad for the engine for sure.

 

Thanks, that's some good info there. I'll try and be a little more diligent with the search feature next time too. I think I'll give all that a try and avoid the 'stealership' for now. They recently wanted to charge me 600 to replace my horn.

 

if its extremely loud I would look for gaskets around the turbo/cat area

 

ImTheDevil, followed your advice and got the cheap $15 cable off ebay and downloaded the free version of vag-com from ross tech. Looks like you nailed it with your first diagnosis...

These codes came up after auto-scan:

#16684 - Random/Multiple Cylinder Misfire Detected
#16688 - Cyl. 4 Misfire Detected
#16687 - Cyl. 3 Misfire Detected

Does the fact that this is multiple misfires point to faulty coil packs? What should be my next step?

 

I would replace Coilpack 3 &4 and may want to do all at the same time. The factory ones have been known to go ...Had all 4 of mine go in 12 month time frame. And may want to keep a couple in your trunk. Just in case!

 

Car is now running great!

I replaced all the coil packs and spark plugs and took her for a spin -- no issues at all. It was very easy to do and so much cheaper than taking it to the dealership!