So what would be a seafoam treatment? and how would it help? sorry i am new to euro cars i have always dealt with domestic and there are so many things that are diferent.

 

Usually, it refers to running about 1/3 of a can of Sea Foam through a vacuum line into the engine. You're supposed to do it fairly fast so the engine stalls. Then you're supposed to let it sit for a while. Then you start it up and it will usually smoke quite a bit, which is supposed to be the crap it loosened up burning off. (True? I don't know.)

You can also add some to your gas tank. You can also add some to your oil a day or two before you do an oil change.

 

What vacuum lines should I check? My A4 is also vibrating. I just replaced the plugs and coils, still getting misfires for 1 2 and 3.

 

Can be any of them. The rubber for them falls apart. And it can be hard to tell because of the cloth covering. If the engine's running that poorly then I'd start by looking at the bigger lines. And check your suction pump (AKA vacuum booster) to make sure it hasn't come apart.

 

I took some carb cleaner. Ran it all over the vacuums on the diagram under the hood. No luck.

First thing I did was clean the MAF. The owner before bought an aftermarket cold air intake. I thought for sure that would be the problem. The MAF responded a little better after the cleaning. I took it out and it threw the fault code for it but with the MAF in I'm not getting a code.

Next the coils and plugs replaced. Drove a lot better but still getting the vibration and CEL codes 300,301,302,303. So vacuum lines weren't any luck either.

Would you recommend SeaFoaming it? How do you get in in the vacuum lines and which one? I am really at a loss here. It seemed for most people on here with misfires and idle vibration that the coils made the difference.