I actually have a can of Seafoam on hand right now that I use in the winter months for my motorcycle. How would I go about using Seafoam on the vacuum system?

Another thing, I can go get vacuum lines tomorrow. Any idea what sizes, how much, and what material I should get?

 

When you search the forums for seafoam, a wealth of responses will pull up (to make life easier "go advanced" and have it filter just posts under the B5 section) I believe there is one that I started where someone gave me an incredibly useful link to a 2.8 DIY for where you put the seafoam.

As for the vac lines, I'm pretty sure its a 3.5mm tube, and you'll need about a foot and a half (get two feet to be safe) if you're just doing the small bits and pieces that sit on the top of the intake mani, 5-6 if you're going to tackle the lines going to the combi valves on the back of the engine as well.

 

blauparts has a vac line kit on there site. Has different mm sizes for the lines. Like devil said take the pcv system apart and clean followed up by replacing the crap plastic lines with 5/8 high temp hose and cut near the ends of the connectors and slip on with clamps. I have to bite the bullet and order the pcv hoses since I have blow out now at the ends. Clean out the throttle body and icv (idle control valve), black cylinder next to the throttle body. Get into the practice of seafoaming your car. Our engines are dirty and it needs it every so often .

 

I will be doing the Seafoam in the morning, and if I see that there are issues even after that, I will be replacing the vac lines on the spot. Funny how I'm doing all this work at a hardware store that my friend manages so I can get the parts there if needed. If I still have issues with the idle, I will do all the cleaning that you guys brought up. I really hope this works. If it does, then all that's left is the front passenger trans axle.

 

Hey, I also am an owner of a 1998 Audi a4 1.8t, but am a new owner. My knowledge of cars(esp. Audi's) is moderate at best, but my car just randomly stopped starting one day. Long story short i took it to a shop and after fixing it they told me there is a common problem with my model where it was difficult to tell what level to idle on, and I might need to take it to a dealership and they can reset something inside of it. Sorry i can't be more specific, but maybe this will ring a bell for someone.

 

What I would do first is do what took me months to come to the conclusion to get which was a Vag-Com. Seriously, if you can't afford one straight from Ross-Tech, buy a third party cable from eBay, and get the free version of the Vag-Com software. It will do wonders to figure out what's really going on with your car.